Write documentation for the Lua API and generate markdown for the docs

[lionkor]

Related to BeamMP/BeamMP-Server#355. Basically, we want to generate the Lua Docs page from the LuaAPI.cpp or LuaAPI.h file. This can be a script, it can use doxygen, it can use whatever.

It needs to:

• Generate markdown for the docs.beammp.com page (in the right flavor)
• Make the script maintainable and run it in CI/CD

[carsakiller]

As mentioned before, I would be interested in helping writing definition files for the API for use with the Lua Language Server. The definition files could be generated at the same time as the markdown to make things easier to maintain and more consistent.

We could potentially write all the documentation using LuaCATS annotations and then use the export documentation feature of the language server to generate JSON and Markdown from the definition files. Although this would require some testing.

The other option is to define the entire API in JSON/XML/YAML and then generate the Markdown and LuaCATS annotations from that. It would allow more customization and control, but would also require a custom script.