Add API documentation generation and use Markdown (#160)

* Add package API documentation generation

Add generation of the API documentation for akkudoktoreos
and akkudoktoreosserver packages.

The API documentation is generated by the Sphinx autosummary extension.

Signed-off-by: Bobby Noelte <[email protected]>

* Enable Google style source commenting and documentation generation.

Enable automatic documentation generation from Google style docstrings in the source.

Signed-off-by: Bobby Noelte <[email protected]>

* Check Google style source commenting.

Check Google style commenting by the appropriate ruff rules.

Commenting is _NOT_ enforced. Missing docstrings are ignored.

Minor commenting quirks of the code base are adapted.

Signed-off-by: Bobby Noelte <[email protected]>

* Improve Markdown handling and switch to Markdown documentation.

Switch to Markdown for the documentation files to improve the user and developer experience (see issue #181).

Keep files with special directives for automatic API documentation in RST format. The
directives expect RST.

Also add dummy handling for openai/ swagger server documentation. The openai interface definition is
for now taken from the fastapi PR as EOS will switch to fastAPI.

Signed-off-by: Bobby Noelte <[email protected]>

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Signed-off-by: Bobby Noelte <[email protected]>
Co-authored-by: Normann <[email protected]>