Develop Bluez docs parser to use as introspection

[igo95862]

Bluez does not provide the introspection XML making it difficult to develop binds: bluez/bluez#296

However, they do provide D-Bus documentation in restructuredText: https://github.com/bluez/bluez/tree/master/doc

rST has a native Python implementation called docutils. It should be possible to parse the the rST files and and have a programatic representation of the API: https://docutils.sourceforge.io/docs/dev/hacking.html#parsing-the-document

[igo95862]

Looks like @arkq already done some work on parsing the Bluez documentation: https://github.com/Samsung/BlueZoo/blob/master/scripts/bluez-interfaces.py

It is using pyparsing. My idea was to use the Python native rST parser. Not sure what is the better approach.

I plan on separating the introspection and code generator in the future python-sdbus version. This means you would be able to programatically create introspection objects and feed them to the code generator.