Include a simple config for the polarion plugin

[psss]

So far the Pylero documentation was only mentioned in examples. Let's make it easier to get started by providing a simple config.

Pull Request Checklist

• write the documentation

[psss]

@happz, originally I was thinking about including the example and link directly in the plugin but including the anonymous rst link in the plugin docstring caused the following error:

  File "/home/psss/.local/share/hatch/env/virtual/tmt/v_yBwOy-/docs/lib/python3.12/site-packages/docutils/nodes.py", line 2033, in dispatch_visit
    return method(node)
           ^^^^^^^^^^^^
  File "/home/psss/git/tmt/tmt/utils.py", line 6959, in unknown_visit
    raise GeneralError(f"Unhandled ReST node '{node}'.")
tmt.utils.GeneralError: Unhandled ReST node '<target anonymous="1" ids="['target-1']" refuri="https://github.com/RedHatQE/pylero"/>'.

Seems to be related to our custom parsing in the tmt.utils.parse_rst() function. Could you possibly look into that?

[happz]

@happz, originally I was thinking about including the example and link directly in the plugin but including the anonymous rst link in the plugin docstring caused the following error:
...
Seems to be related to our custom parsing in the tmt.utils.parse_rst() function. Could you possibly look into that?

Sure, it's far from complete (and perfect). I'll add a unit test for it, and implement link rendering in the process.