Add X2 peers support for symmetry with XN peers.

As with Radio Units and cells organize a registry of peers and start to handle
that registry generally everywhere. The registry is still populated with only
LTE peers on enb and only NR peers on gnb, but the only place that is aware of
that is registry loading routine.

Tests will be added later as full tests for generic MultiRU.

Rendered gnb.cfg stays the same, but there is a small change in rendered enb
but the config remains with the previous semantic as before hereby patch:

```
$ ./pythonwitheggs slapos-render-config.py && xdiff -w config/{old,out}
```

```diff
diff --git a/config/old/enb.cfg b/config/out/enb.cfg
index 5842dfc22..1a2c41b6b 100644
--- a/config/old/enb.cfg
+++ b/config/out/enb.cfg
@@ -22,6 +22,7 @@
     },
   ],
   gtp_addr: "127.0.1.1",
+  x2_peers: [],
   enb_id: 0x1A2D0,

   // LTE cells
```

Use $ref to share definitions taken from either generic enb or cell object.

software/ors-amarisoft: Add notices to ORS and generic softwares what they do and intended usage area

Both software.cfg and software-ors.cfg became trivial wrappers over their bases
- so move bases to be directly software.

After previous patch this rendering became unneeded. And after we stop
render-templates becomes unneeded too, so say goodbye to it as well.

software/ors-amarisoft: enb+ue: Switch to JSON schemas as the primary source of defaults; stop rendering them

JSON schemas for eNB/gNB and UE specify defaults for many parameters and the
software release use those defaults when parameters are not explicitly
specified on the instantiation.

Some primary defaults - for bandwidth and n_antenna DL/UL - were setup in
render-templates and propagated through all places to avoid duplicating them.

Defaults for many other parameters were duplicated in both JSON schemas and in
the code that handles those parameters.

To avoid this duplication we either need to extend render-templates and put
defaults for all the other many parameters there, or just switch to JSON
schemas to be primary source of those defaults, and use the schemas on
instantiation by automatically loading them and extracting defaults for all
parameters from there.

I decided to go the second way because it avoids additional layer of rendering
and the need to keep on remembering not to put raw defaults in the JSON
schemas. Evidently this is the same approach that Rapid CDN is going to take
(see nexedi/slapos!1380 for details).

In this patch we stop rendering JSON schemas and keep their last rendered
result. In the later patches we will handle formed duplication there and go on
to further merge enb and gnb.

UE is handled brutally for now, because it will be much reworked after.

Actually loading JSON schemas is left as TODO as I do not have resources to
implement that now. Still this step is needed as precondition for further
patches. I hope bit of duplication for enb/gnb parameters is ok, given that
they are now centrally maintained and corresponding TODO warning is in place.

software/ors-amarisoft: enb/generic: Move LTE and NR cell definitions to schemas under cell/lte/ and cell/nr/

And reuse bits from there for ORS cell-related parameters.

Preparatory step to handle cell as separate object and a bit less code duplication.

A bit less duplication.

For uniformity with NR which already has bandwidth specified as number in MHz.

For ORS mode everything stays as is which inputs bandwidth as string with MHz
suffix, e.g. "20 MHz" instead of number `20`.

We currently have 2 kinds of software:

- ORS, whose intended usage is small private networks, and
- generic, whose intended usage is small-to-medium networks.

and currently they both share defaults for their parameters inherited from ORS.
But what is appropriate for small private networks, might be not so appropriate
for medium networks.

For example ORS has default enb_id/gnb_id, but in a network with 100 nodes, it
is better to force every node to be explicitly assigned an id and error
otherwise. Similarly for cells ORS has defaults for cell_id, but in network
with many nodes, cell_id needs to be explicitly assigned. With having a default
there is also a chance to misspell the parameter name, and do not notice it
because the software will instantiate without an error but work incorrectly.

So in this patch we tighten the defaults for generic:

- enb_id, mme_list become non-optional for LTE
- gnb_id, afm_list become non-optional for NR
- plmn_list becomes non-optional for both LTE and NR. The format is different
  in between RATs and so later we will use plmn_list and plmn_list_5g when
  merging enb and gnb.

- the following parameters of LTE cells now needs to be explicitly configured:
  rf_mode, dl_earfcn, bandwidth, cell_id, pci, tac.
- the following parameters of  NR cells now needs to be explicitly configured:
  rf_mode, dl_nr_arfcn, nr_band, bandwidth, cell_id, pci.

We rework ORS mode to translate its own set of parameters and defaults into
generic enb/gnb parameters.

We similarly pull some global generic defaults into instance-enb.cfg.jinja2
with the idea that they could be maintained in one central place. In the future
it would be good to automatically load them from JSON schemas to avoid
duplication.

This patch should be backward compatible for ORS, but it introduces the change
in cell_id and pci in rendered enb.cfg which become 1 instead of 0:

    --- a/config/old/enb.cfg
    +++ b/config/out/enb.cfg
    @@ -33,9 +33,9 @@
           n_antenna_dl: 2,
           n_antenna_ul: 2,

    -      cell_id:    0x00,
    +      cell_id:    0x01,
           tac:        0x0001,
    -      n_id_cell:  0,
    +      n_id_cell:  1,
           root_sequence_index: 204,
           dl_earfcn:  36100,
           inactivity_timer: 10000,

The defaults for those parameters according to instance-enb-input-schema.json
are 0x01 and 1. And it looks like enb.jinja2.cfg was changed to emit them starting from
0 instead of 1 in c4d0958e due to probable thinko in that patch because before
that patch those parameters were emitted as 0x01 and 1:

    nexedi/slapos@c4d0958e

and, once again, the schema says their defaults should be 0x01 and 1 as well.

The rest of the changes in rendered enb.cfg and gnb.cfg should not introduce
any semantic difference. Please see the appendix for full details.

--------

Appendix. Diff for rendered enb.cfg and gnb.cfg before and after this patch:

```
$ ./pythonwitheggs slapos-render-config.py && xdiff -w config/{old,out}
```

```diff
diff --git a/config/old/enb.cfg b/config/out/enb.cfg
index 89862f1d9..5842dfc22 100644
--- a/config/old/enb.cfg
+++ b/config/out/enb.cfg
@@ -33,9 +33,9 @@
       n_antenna_dl: 2,
       n_antenna_ul: 2,

-      cell_id:    0x00,
+      cell_id:    0x01,
       tac:        0x0001,
-      n_id_cell:  0,
+      n_id_cell:  1,
       root_sequence_index: 204,
       dl_earfcn:  36100,
       inactivity_timer: 10000,
@@ -102,8 +102,11 @@
   ],
   cell_default: {
     plmn_list: [
-      "00101",
-
+      {
+        plmn: "00101",
+        reserved: false,
+        attach_without_pdn: false,
+      },
     ],
     cyclic_prefix: "normal",

diff --git a/config/old/gnb.cfg b/config/out/gnb.cfg
index 1df699a22..635c4baf2 100644
--- a/config/old/gnb.cfg
+++ b/config/out/gnb.cfg
@@ -22,7 +22,7 @@
     },
   ],
   gtp_addr: "127.0.1.1",
-
+  xn_peers: [],
   gnb_id_bits: 28,
   gnb_id: 0x12345,
   en_dc_support: true,
@@ -142,6 +142,7 @@

   nr_cell_default: {
     ssb_period: 20,
+
     plmn_list: [
       {
         plmn: "00101",
@@ -151,10 +152,10 @@
           {
             sst: 1,
           },
-
         ],
       },
     ],
+
     si_window_length: 40,
     cell_barred: false,
     intra_freq_reselection: true,
```

Else enb treats args="" unset and implicitly uses /dev/sdr0 by default.

We do not want implicit default behaviour -> we want to see an error.

We currently have support for a3_offset and a3_time_to_trigger only, while
there is also a3_hysteresis plus at least a1_*, a2_* and probably other parameters.

Simple A3-only based meas_config tuning might be appropriate for ORS, but for
generic enb it is better to expose full control which I do not currently feel
good to implement right now. So do not expose it at all on generic to avoid
establishing a public API yet.

enb.jinja2.cfg already has corresponding comments:

  {#  TODO fully expose lte meas_config_desc in generic SR #}
    meas_config_desc: {
    ...

  {#  TODO fully expose nr meas_config_desc in generic SR #}
    meas_config_desc: {

- Indicate that it is not for ORS, but for generic case.
- Move ue to the end, to where it logically belongs.
- Indicate shared instances clearly with clear visually appearing indent.
  For now it is only about SIM card, but later we will be adding more kinds of
  shared instances, so it will be needed to clearly see on the UR if an item is
  a kind of service, or a shared instance of a service.

There is now only 2 kinds of softwares - ORS and generic, and their cfg.json
will diverge with ORS staying as it is now for backward compatibility, and
generic gaining more features and more kind of shared instances. That means
that it no longer makes sense to render those two from a common source.

-> Stop rendering them and leave previous rendered result in place for further manual edits.

Previously, e.g. for ORS it was:

    enb                 index=0
    gnb                 index=1
    core-network        index=2
    core-network-slave  index=3

which resulted in the following appearance order on SlapOS Master UI:

    gnb
    core-network
    core-network-slave
    enb

Note that enb comes last instead of being first as originally intended.

That happens because SlapOS Master treats index=0 as being unset and puts all
items with unset index in the end.

-> Fix this by starting explicitly-set indices from 1.

Now, for ORS, the order on UI is

    enb
    gnb
    core-network
    core-network-slave

As explained in the previous patch now once we have software.cfg and
software.cfg.json, json-schemas started to analyze them instead of skipping
software/ors-amarisoft/ completely, and it started to complain about missing
response schemas, for example:

    ERROR: test_ors-amarisoft_software_cfg_json (slapos.test.test_json_schema.TestJSONSchemaValidation)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "/srv/slapgrid/slappart91/srv/runner/software/45a1e838784afb18daf420009d925c78/eggs/jsonschema-4.17.3-py3.9.egg/jsonschema/validators.py", line 909, in resolve_from_url
        document = self.store[url]
      File "/srv/slapgrid/slappart91/srv/runner/software/45a1e838784afb18daf420009d925c78/eggs/jsonschema-4.17.3-py3.9.egg/jsonschema/_utils.py", line 28, in __getitem__
        return self.store[self.normalize(uri)]
    KeyError: 'file:///srv/slapgrid/slappart91/srv/project/slapos/software/ors-amarisoft/instance-ue-schema.json'

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 1503, in open_local_file
        stats = os.stat(localfile)
    FileNotFoundError: [Errno 2] No such file or directory: '/srv/slapgrid/slappart91/srv/project/slapos/software/ors-amarisoft/instance-ue-schema.json'

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "/srv/slapgrid/slappart91/srv/runner/software/45a1e838784afb18daf420009d925c78/eggs/jsonschema-4.17.3-py3.9.egg/jsonschema/validators.py", line 912, in resolve_from_url
        document = self.resolve_remote(url)
      File "/srv/slapgrid/slappart91/srv/runner/software/45a1e838784afb18daf420009d925c78/eggs/jsonschema-4.17.3-py3.9.egg/jsonschema/validators.py", line 1018, in resolve_remote
        with urlopen(uri) as url:
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 214, in urlopen
        return opener.open(url, data, timeout)
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 517, in open
        response = self._open(req, data)
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 534, in _open
        result = self._call_chain(self.handle_open, protocol, protocol +
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 494, in _call_chain
        result = func(*args)
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 1481, in file_open
        return self.open_local_file(req)
      File "/srv/slapgrid/slappart91/srv/runner/shared/python3/dd8479ce2a2b9dff51f7185535dd0403/lib/python3.9/urllib/request.py", line 1520, in open_local_file
        raise URLError(exp)
    urllib.error.URLError: <urlopen error [Errno 2] No such file or directory: '/srv/slapgrid/slappart91/srv/project/slapos/software/ors-amarisoft/instance-ue-schema.json'>

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
      File "/srv/slapgrid/slappart91/srv/project/slapos/slapos/test/test_json_schema.py", line 72, in run
        resolver.resolve(software_type_definition['response'])
      File "/srv/slapgrid/slappart91/srv/runner/software/45a1e838784afb18daf420009d925c78/eggs/jsonschema-4.17.3-py3.9.egg/jsonschema/validators.py", line 898, in resolve
        return url, self._remote_cache(url)
      File "/srv/slapgrid/slappart91/srv/runner/software/45a1e838784afb18daf420009d925c78/eggs/jsonschema-4.17.3-py3.9.egg/jsonschema/validators.py", line 914, in resolve_from_url
        raise exceptions.RefResolutionError(exc)
    jsonschema.exceptions.RefResolutionError: <urlopen error [Errno 2] No such file or directory: '/srv/slapgrid/slappart91/srv/project/slapos/software/ors-amarisoft/instance-ue-schema.json'>

-> Fix this and all other similar errors by adding stub response schemas for all objects that is possible to instantiate.

Previously json-schemas tests were passing on software/ors-amarisoft but the
status was misleading: since json-schemas check only software.cfg.json, and
until recently - before the patch to switch RU type to be a runtime parameter,
there was _no_ such file in here, nothing about software-*.cfg.json was checked at all.

But after the switch we started to have software.cfg and software.cfg.json
files which json schemas checks and errors start to appear.

Here we fix the following error popping up due to extra blank lines around "ue" entry in software.cfg.json:

    FAIL: test_ors-amarisoft_software_cfg_json_format (slapos.test.test_json_schema.TestJSONSchemaValidation)
    ----------------------------------------------------------------------
    Traceback (most recent call last):
      File "/srv/slapgrid/slappart91/srv/project/slapos/slapos/test/test_json_schema.py", line 85, in run
        self.assertEqual(
    AssertionError: Lists differ: ['{',[145 chars]{', '    "ue": {', '      "title": "UE",', '  [1344 chars] '}'] != ['{',[145 chars]{', '', '    "ue": {', '      "title": "UE",',[1352 chars] '}']

    First differing element 5:
    '    "ue": {'
    ''

    Second list contains 2 additional elements.
    First extra element 48:
    '  }'

    Diff is 1703 characters long. Set self.maxDiff to None to see it.

Previously RU type was static parameter of particular software - it was
possible to instantiate cells only with selected RU type for particular template.

In MultiRU it will be possible to generally instantiate all kind of cells -
LTE/NR and TDD/FDD all at the same time and each served by a different kind of Radio Unit.

-> Switch RU to be runtime parameter as a preparatory step for that.

There is now only two software releases:

  - ORS (software-ors.cfg), and
  - generic (software.cfg).

ORS behaviour stays the same as before here by patch.

For generic each cell in cell_list now needs to explicitly specify which kind
of RU it wants to use and with which parameters. There are less defaults: for
example which CPRI board and SFP port to use now needs to be explicitly
specified.

Only ORS tests are left for now. The old test{LOPCOMM,M2RU,ANY} did not
exercised any driver-specific functionality and until recently were not run at
all due to '-' in their file name. We remove them for now and we will add tests
for generic in a soon follow-up patch after switching LTE/NR cell type to also
be a runtime parameter.

Backward compatibility:

  * nothing changes for ORS
  * for generic all RU-related parameters are now moved from cell_list to
    cell_list.ru, there are several renames and besides ru_type ru_link_type also
    needs to be specified. Please see new RU-related JSON schemas added into
    ru/ for details. Cell_list itself now also does not provide a default with
    one cell - if no cells are configured no cells are instantiated.

--------

Appendix. Diff for rendered enb.cfg and gnb.cfg before and after this patch:

```
$ ./pythonwitheggs slapos-render-config.py && xdiff -w config/{old,out}
```

```diff
diff --git a/config/old/enb.cfg b/config/out/enb.cfg
index 1b39f7044..89862f1d9 100644
--- a/config/old/enb.cfg
+++ b/config/out/enb.cfg
@@ -6,7 +6,7 @@

   // Radio Units
   rf_driver: {
-      // default-RU 2T2R  (ors)
+      // CELL-RU 2T2R  (sdr)
       name: "sdr",
       args: "dev0=/dev/sdr0",
       rx_antenna:"tx_rx",
@@ -27,7 +27,7 @@
   // LTE cells
   cell_list: [

-    // default  (default-RU)
+    // CELL  (CELL-RU)
     {
       rf_port:      0,
       n_antenna_dl: 2,
@@ -90,11 +90,11 @@
       srs_hopping_bandwidth: 0,
     },

-    drb_config: "default-drb.cfg",
+    drb_config: "CELL-drb.cfg",

     sib_sched_list: [
       {
-        filename: "default-sib23.asn",
+        filename: "CELL-sib23.asn",
         si_periodicity: 16,
       },
     ],
diff --git a/config/old/gnb.cfg b/config/out/gnb.cfg
index 05deb5ada..1df699a22 100644
--- a/config/old/gnb.cfg
+++ b/config/out/gnb.cfg
@@ -6,7 +6,7 @@

   // Radio Units
   rf_driver: {
-      // default-RU 2T2R  (ors)
+      // CELL-RU 2T2R  (sdr)
       name: "sdr",
       args: "dev0=/dev/sdr0",
       rx_antenna:"tx_rx",
@@ -35,7 +35,7 @@
   // NR cells
   nr_cell_list: [

-      // default  (default-RU)
+      // CELL  (CELL-RU)
       {
         rf_port:      0,
         n_antenna_dl: 2,
@@ -136,7 +136,7 @@
           ],
         },

-        drb_config: "default-drb.cfg",
+        drb_config: "CELL-drb.cfg",
       },
   ],
```

Previously rf_mode was static parameter of particular software - it was
possible to instantiate cells only of the mode selected for particular template.

In MultiRU it will be possible to generally instantiate all kind of cells -
LTE/NR and TDD/FDD all at the same time.

-> Switch rf_mode to be runtime parameter as a preparatory step for that.

Software for ORS becomes just software-ors.cfg with software-tdd-ors.cfg
providing backward compatibility proxy as we have many ORS'es currently
deployed with that software-release URL. For other softwares backward
compatibility is not preserved including for software-fdd-ors.cfg because we
practically have very few deployments with those.

To show tdd_ul_dl_config only for TDD we use conditional feature of new JSON-editor.

Backward compatibility: nothing changes for ORS, for everything else rf_mode
now needs to be explicitly set in cell parameters if it is not TDD.

Rendered enb.cfg and gnb.cfg stay the same.

Similarly with cell_list, organize a loop in under nr_cell_list and emit
configuration for each NR cell we have.

Tests will be added later as full tests for generic MultiRU.

Only trivial space and comments changes in rendered gnb.cfg

Backward compatibility: no change for ORS and everything else.

So far CA was setup only for lte case and it is possible to simplify generation
of all pair of cells to be done without extra loop and state.

Tests will be added later as full tests for generic MultiRU.

Backward compatibility: no change for ORS, which has only one cell, and
rendered enb.cfg and gnb.cfg stay the same.

For uniformity with LTE where it already is.

We do not expose it in ORS schema because it will be exposed only in generic
LTE and NR schemas, but for ORS schemas I prefer to keep them intact myself.

Tests will be added later as full tests for generic MultiRU.

Backward compatibility: no change for ORS and everything else.

Diff for rendered configs:

$ ./pythonwitheggs slapos-render-config.py && git diff -w --no-index config/{old,out}
diff --git a/config/old/gnb.cfg b/config/out/gnb.cfg
index 5849bb924..b8a385a71 100644
--- a/config/old/gnb.cfg
+++ b/config/out/gnb.cfg
@@ -56,6 +56,7 @@
     subcarrier_spacing: 30,
     ssb_pos_bitmap: "10000000",

+    root_sequence_index: 1,
     inactivity_timer: 10000,

       // Handover
@@ -176,7 +176,6 @@
     intra_freq_reselection: true,
     q_rx_lev_min: -70,
     q_qual_min: -20,
-    root_sequence_index: 1,
     sr_period: 40,
     dmrs_type_a_pos: 2,
     prach: {

As with Radio Units organize a registry of cells and start to handle that
registry generally everywhere. Make parameters that configure cells, for
example tdd_ul_dl_config, dl_earfcn, bandwidth, pci, etc to be per-cell.

Cell registry is still populated from cell_list and slapparameter_dict.

Tests will be added later as full tests for generic MultiRU.

Rendered enb.cfg and gnb.cfg stay practically the same.

Backward compatibility: no change for ORS; For everything else cell parameters
stop to be global and are moved to cell_list.

--------

Appendix. Diff for rendered enb.cfg and gnb.cfg before and after this patch:

```
$ ./pythonwitheggs slapos-render-config.py && xdiff -w config/{old,out}
```

```diff
diff --git a/config/old/enb.cfg b/config/out/enb.cfg
index 5c6743c21..1b39f7044 100644
--- a/config/old/enb.cfg
+++ b/config/out/enb.cfg
@@ -1,6 +1,3 @@
-
-
-
 {
   log_options: "all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,s1ap.level=debug,s1ap.max_size=1,x2ap.level=debug,x2ap.max_size=1,rrc.level=debug,rrc.max_size=1,ngap.level=debug,ngap.max_size=1,xnap.level=debug,xnap.max_size=1,phy.level=info,file.rotate=1G,file.path=/dev/null",
   log_filename: "log/enb.log",
@@ -93,11 +90,11 @@
       srs_hopping_bandwidth: 0,
     },

-    drb_config: "drb",
+    drb_config: "default-drb.cfg",

     sib_sched_list: [
       {
-        filename: "sib",
+        filename: "default-sib23.asn",
         si_periodicity: 16,
       },
     ],
diff --git a/config/old/gnb.cfg b/config/out/gnb.cfg
index 6b04559c6..1fa637925 100644
--- a/config/old/gnb.cfg
+++ b/config/out/gnb.cfg
@@ -1,6 +1,3 @@
-
-
-
 {
   log_options: "all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,s1ap.level=debug,s1ap.max_size=1,x2ap.level=debug,x2ap.max_size=1,rrc.level=debug,rrc.max_size=1,ngap.level=debug,ngap.max_size=1,xnap.level=debug,xnap.max_size=1,phy.level=info,file.rotate=1G,file.path=/dev/null",
   log_filename: "log/enb.log",
@@ -77,7 +74,6 @@
     manual_ref_signal_power: true,
     ss_pbch_block_power: 8,

-
     tdd_ul_dl_config: {
       pattern1: {
          period: 5, /* in ms */
@@ -148,7 +144,7 @@
       ],
     },

-    drb_config: "drb",
+    drb_config: "default-drb.cfg",
   },
   ],
   nr_cell_default: {
```

Most were already so, but sdr_number and cpri_mult were not. We need to be able
to use different SDR boards and with different CPRI speed, so make those
parameters to be per-RU as well.

Backward compatibility: no change for ORS; For CPRI-based cases sdr_number and cpri_mult become per-RU.

Like e.g. txa0cc00_center_frequency, rxa0cc00_center_frequency_earfcn, etc -
because different units needs to use different parameters.

cron_schedule is renamed to -> reset_schedule to better reflect its meaning.

user-authorized-key remains to be global as this is per-eNB nor per-RU
property, but is likely unneded in the future. Corresponding FIXME is added to
highlight this.

Backward compatibility: no change for ORS; lopcomm parameters become per-cell and need adaptation.

Add code to organize a registry of Radio Units and handle that registry generally everywhere.

RU registry is still populated from cell_list and in practice there still can
be radio units only of the same type, but besides slaplte.load_ru_and_cell
which is aware of that, the rest of the code tries to do everything as if
RUs of different type could be present simultaneously.

Now it is not only lopcomm who can do multiCELL, but also sunwave and SDR as well.

gNB also starts to gain support for cell_list, because cell_list loading is
uniformly applied to both eNB and gNB. However, since enb.cfg is not yet
prepared to handle multiple NR cells yet, there is an assert that in case of NR
there is only one RU/cell present there. We will remove this limitation in a
follow-up patch.

Later we will also change the loading to load RU descriptions from shared instances
and they won't be constrained to be Radio Units of the same type. But we need
to prepare a lot to be able to do that.

One more step forward towards MultiRU.

Tests will be added later as full tests for generic MultiRU.

Backward compatibility: no change for ORS and practically no breaking change for everything else.

--------

Appendix. Diff for rendered enb.cfg and gnb.cfg before and after this patch:

```
$ ./pythonwitheggs slapos-render-config.py && git diff -w --no-index config/{old,out}
```

```diff
diff --git a/config/old/enb.cfg b/config/out/enb.cfg
index 884483b0a..cafdf42be 100644
--- a/config/old/enb.cfg
+++ b/config/out/enb.cfg
@@ -1,24 +1,22 @@

-
 {
   log_options: "all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,s1ap.level=debug,s1ap.max_size=1,x2ap.level=debug,x2ap.max_size=1,rrc.level=debug,rrc.max_size=1,ngap.level=debug,ngap.max_size=1,xnap.level=debug,xnap.max_size=1,phy.level=info,file.rotate=1G,file.path=/dev/null",
   log_filename: "log/enb.log",

-
+  // Radio Units
   rf_driver: {
+      // default-RU 2T2R  (ors)
       name: "sdr",
       args: "dev0=/dev/sdr0",
-
       rx_antenna:"tx_rx",
       tdd_tx_mod: 1,
   },
-  tx_gain: 62,
-  rx_gain: 43,
-
+  tx_gain: [62, 62],
+  rx_gain: [43, 43],
   com_addr: "127.0.1.2:9001",
   // LTE core network
   mme_list: [
@@ -36,6 +34,8 @@

   // LTE cells
   cell_list: [
+
+    // default  (default-RU)
     {
       rf_port:      0,
       n_antenna_dl: 2,
diff --git a/config/old/gnb.cfg b/config/out/gnb.cfg
index fd57ca3dc..7818b4ea8 100644
--- a/config/old/gnb.cfg
+++ b/config/out/gnb.cfg
@@ -1,24 +1,22 @@

-
 {
   log_options: "all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,s1ap.level=debug,s1ap.max_size=1,x2ap.level=debug,x2ap.max_size=1,rrc.level=debug,rrc.max_size=1,ngap.level=debug,ngap.max_size=1,xnap.level=debug,xnap.max_size=1,phy.level=info,file.rotate=1G,file.path=/dev/null",
   log_filename: "log/enb.log",

-
+  // Radio Units
   rf_driver: {
+      // default-RU 2T2R  (ors)
       name: "sdr",
       args: "dev0=/dev/sdr0",
-
       rx_antenna:"tx_rx",
       tdd_tx_mod: 1,
   },
-  tx_gain: 62,
-  rx_gain: 43,
-
+  tx_gain: [62, 62],
+  rx_gain: [43, 43],
   com_addr: "127.0.1.2:9001",
   // NR core network
   amf_list: [
```

For LTE tdd_ul_dl_config is

    enum [
         "[Configuration 2] 5ms 2UL 6DL (default)",
         "[Configuration 6] 5ms 5UL 3DL (maximum uplink)"
    ],

but default was outside of that enum. The code in enb.jinja2.cfg actually uses
the first option from the enum as the default.

-> Fix default in schema.

tdd_ul_dl_config in NR seems to be already correct.

There is cell_list.*.cpri_port_number that is used insted from the beginning.

-> Remove unused cpri_port from scheamas.

Previously type of emulated UE was static parameter of particular software
release - it was possible to simulate UE and attach to cells only of the RAT of
particular template.

In MultiRU it will be possible to generally emulate all kind of UEs - both LTE
and NR all at the same time, and attach them to LTE and NR cells
simultaneously.

-> Switch type of UE to be runtime parameter as a preparatory step for that.

URLs of software releases changes (we remove lte and nr in names), but here we
do not care about backward compatibility because currently there are just a few
UEsim deployments and migration should be easy.

Less code duplication

SIM card object is useful to have not only for Core Network - we will also use
it for UE configutation. Move SIM schema into common place as a preparatory step.

K and IMSI are orthogonal to RAT and, similarly to how we keep default
n_antenna_dl/ul independent of RAT we can do so with this default UE parameters.

ORS does not support UEsim as indicated by `if bbu != ors` in software.cfg.json.jinja2.

Amends f3f1cb46 (software/ors-amarisoft: Start to introduce ORS mode) because
that patch started to really reject instantiating ue-* on ORS.

Those were unused because software.cfg.json.jinja2 explicitly enables UEsim only for bbu != 'ors'.

Soon we are going to make rf_mode a runtime parameter and so there
won't be TDD and FDD in software names anymore.

Prepare to that and make --delete to remove the exact set of files that
render-template actually generates instead of becoming a noop after "runtime
rf_mode" restructuring.

We are currently querying it in instance.cfg and later, once again, in e.g. instance-enb.jinja2.cfg .

However ORS mode will need to adjust slapparameter_dict with ORS defaults
and pass it further to generic enb. So it won't work if we use
slapparameter_dict obtained the second time because the second query will
return unadjusted original slapparameter_dict.

In this patch we are only doing preparatory step - redo the code not query the
master from instance-{enb,ue}.jinja2.cfg and work with slapparameter_dict and
slap_configuration already queried by instance.cfg

For UE the change is trivial.

For eNB instance-enb.jinja2.cfg used to set the defaults for com, mme, amf and
gtp in the same section used for the second query. We rework those defaults to
be applied to slapparameter_dict via jinja2 - via the same way we are going to
later use in ORS mode.

Handling defaults for everything besides gtp_addr is straightforward. For
gtp_addr it has the semantic difference when explicitly given, and given only
implicitly. In the latter case the intent of original code is to autodetect
whether to use an address on loopback, or externally-visible address.

Original code used the check for emptiness of mme_list/amf_list as the
condition for "use loopback". Since now those lists, after applying their
defaults, are never empty we rework the code to see if core address is on the
loopback or not, and use auto-GTP-on-loopback only if core is also on loopback.
This should, hopefully, be more convenient as it also works ok out of the box
if core is on loopback, but its address was explicitly specified. Previously
for such cases gtp_addr was also needed to be specified, and now it should work
without that.

No change to rendered enb.cfg and gnb.cfg besides whitespace.

Adjust ipv6-random usage in core-network for consistency with enb as well.

For example it is the port that is setup in ru/dnsmasq.jinja2.cfg that is used,
not :port and there it is 5354, i.e. different. :ip is also not used anywhere.

-> Remove them to avoid confusion.

That data structure is really a dict, not list. It is more clear to name it appropriately.

-> Do the renaming but keep cell_list intact as described in JSON schemas so
   that external interface remains unchanged.

Rendered enb.cfg and gnb.cfg remain the same.

Not only inside rendered enb.jinja2.cfg and ue.jinja2.cfg because we will need
that information in slaplte and slaplte is imported by instance-enb and
instance-ue.