supervisord creates a socket with pid in the name, so we have to account
for the space of pid.

Because it's not so easy to know the max size of pids, we just assume 7
places.

otherwise we leak zombie slapproxy processes

To be compatible with buildout (and not only `slapos.recipe.template:jinja2`)

See [#20180416-1138FFA](https://nexedi.erp5.net/bug_module/20180416-1138FFA/)

---

Running this buildout:

```
[buildout]
parts=x

[userinfo]
recipe = slapos.cookbook:userinfo

[x]
recipe = plone.recipe.command
command = echo "Hello user id ${userinfo:pw-uid}"
```


In a slapos patched buildout it outputs: `"Hello user id !py!991"` (which means it's not usable for references directly in other buildout parts)

In a "non patched" buildout fail with error:

```
While:
  Installing.
  Getting section x.
  Initializing section x.
  Getting option x:command.
  Getting section userinfo.
  Initializing section userinfo.

An internal error occurred due to a bug in either zc.buildout or in a
recipe being used:
Traceback (most recent call last):
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 2127, in main
    getattr(buildout, command)(args)
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 681, in install
    [self[part]['recipe'] for part in install_parts]
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1278, in __getitem__
    options._initialize()
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1376, in _initialize
    self._dosub(k, v)
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1431, in _dosub
    v = '$$'.join([self._sub(s, seen) for s in v.split('$$')])
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1495, in _sub
    v = self.buildout[section].get(option, None, seen)
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1278, in __getitem__
    options._initialize()
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1386, in _initialize
    self.initialize()
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1395, in initialize
    self.recipe = recipe_class(buildout, name, self)
  File "/tmp/x/eggs/slapos.cookbook-1.0.62-py2.7.egg/slapos/recipe/userinfo.py", line 13, in __init__
    options['pw-uid'] = pinfo.pw_uid
  File "/tmp/x/env/lib/python2.7/site-packages/zc/buildout/buildout.py", line 1520, in __setitem__
    raise TypeError('Option values must be strings', value)
TypeError: ('Option values must be strings', 991)
```

/cc @Nicolas @alain.takoudjou  @vpelletier 

/reviewed-on nexedi/slapos!321

Proftpd with sftp and virtual users

http://www.proftpd.org/docs/

# Features

 * sftp only is enabled
 * partially uploadloaded are not visible thanks to [`HiddenStores`](http://proftpd.org/docs/directives/linked/config_ref_HiddenStores.html) ( in fact they are, but name starts with `.` )
 * 5 failed login attempts will cause the host to be temporary banned


# TODO

 * only password login is enabled. enabling [`SFTPAuthorizedUserKeys`](http://www.proftpd.org/docs/contrib/mod_sftp.html#SFTPAuthorizedUserKeys) seems to break password only login
 * log rotation
 * make sure SFTPLog is useful (seems very verbose and does not contain more than stdout)
 * make it easier to manage users ( using `mod_auth_web` against an ERP5 endpoint or accepting a list of user/password as instance parameter )
 * allow configuring webhooks when new file is uploaded



----

depends on nexedi/slapos.core!41

/reviewed-on nexedi/slapos!311

_ (underscore) is not supported by apache as domain name
(https://bugzilla.redhat.com/show_bug.cgi?id=1410130), so avoid using it.

/reviewed-on nexedi/slapos!320

The build of nodejs uses python, and python leaking from the system can lead
to unexpected results, thus use provided from SlapOS.

/reviewed-on nexedi/slapos!319

The correct is use require and not required.

fix getInstanceParameterDict typo

/reviewed-by: TrustMe

To run tests from software/proftpd/test

To run tests locally by `python setup.py test`

This is a new kind of test suite that compile software, request instance
with specific parameters and check that the instance works as expected.

@alain, @rafael 

Test is here: https://nexedi.erp5.net/test_result_module/20180412-3688F368/2/view

Its failures which are different from  master one (https://nexedi.erp5.net/test_result_module/20180412-3501D1A/1) seems unrelated to my changes thus I propose to emrge it in and include in next webrunner release.

/reviewed-on nexedi/slapos!317

This reverts commit 1bdac5da.

This commit breaks webrunner resilience importer. This is not the proper fix

Because of this: https://lab.nexedi.com/nexedi/slapos.core/blob/master/slapos/grid/promise/generic.py#L44

When slapgrid run promises, it now save promise logs. Thus we need to logrotate them.
Thanks @Alain.

This recipe will be used to generate promise in etc/plugin dir. It solve the problem of promise eggs
dependencies and allow to set custom parameter to use in promise.

The generated script will looks like:

    import sys
    sys.path[0:0] = [
      ...
    ]

    extra_config_dict = {
      'KEY': 'VALUE'
    }

    CONTENT

CONTENT is a python code, the expected content looks like:

    from namespace.module import RunPromise

then the promise section in buildout will be something like:

    [my-promise]
    recipe = slapos.cookbook:promise.plugin
    eggs =
      NAME
      ...
    output = OUTPUT
    content =
      from namespace.module import RunPromise

    config-KEY = VALUE