Also remove support for very old OSes.

See merge request nexedi/slapos.core!572

When upgrading from a version of slapos.core that does not support
processing instances without a connection to master to one that does,
the following edgecase could occur:

1. some partition is stopped and processed with old version
2. slapos.core is upgraded
3. connection to master is lost
4. offline processing wrongly starts the services of stopped partition

This was because the new version removes the supervisord file for a
partition when the partition is stopped (in online mode) so that the
offline mode can just start all the existing supervisord files. But
since the partitions was never processed in online mode with the new
version, this file was never removed.

To fix this, we use the (now no longer used ) .requested_state file
of the previous version to determine the state of the partition in
offline mode, then we remove both the .requested_state file and the
supervisord file, fixing the discrepancy.

Connection loss may result in `slap.exception.ConnectionError` being
raised during instance processing in addition to `RequestException`.

See merge request !571

   Reuse status gadget so it has the same information as its displayed to the user.

   This is a clean up, there seems to be legacy calls from before the form was refactor. This speeds up form rendering by a lot.

  It is easier to write better tales expressions

See merge request nexedi/slapos.core!569

  On normal UI, this allow use this UI for edit parameters also.

  it only confuses users

   Clean up unrequired code
   Use domsugar rather them createElement for simplification

   This also ensure all events are loaded also

   The form is submitted before the valued input is taken into account due the speed of the robot.

   Value and doc aren't required anymore.

   This make it complies better with ERP5 Form
   Reduce a level on expected options for parameter editor, since there
   is no need to use 'parameter' inside parameter_dict, this was used
   due legacy probably.

   This makes it complies with the ERP5 Form usage.

   Cleans up the calls and remove remove unecessary scripts since they
   were just proxify getAccessStatus for no reason.

    It is mostly broken and nobody keeps the tab open waiting for update. if someone wants real time, it is better to use monitoring app

See merge request nexedi/slapos.core!570

  "disabled" is not actually used anywhere (even on tests), never is already set everywhere.

Slapgrid object makes a connection to master node immediately,
thus if you create a slapgrid object without checking pidfile and if
master node responds very slowly, you may get tons of stucked slapgrid
processes by cron and system may become unusable.

See merge request nexedi/slapos.core!560

Factor test partitions formatting into a separate method to facilitate
customising the formating step in tests that need to do so.

Now that `StandaloneSlapOS.format` calls `slapos node format`, remove
redundant operations in `StandaloneSlapOS.format`, such as updating
the slapproxy.

Always put IPv4 before IPv6 in partition address list, because that's
the existing order and some things rely on that order, such as tests.

A nice example of Hyrum's law in effect.

See merge request nexedi/slapos.core!566

   Destination Reference wasn't used
   Display "Request By", this makes easy to identity if this is a loose instance

   This makes navigation easier.