Add files needed for KApiDox
This will allow us to generate documentation for Craft at https//api.kde.org A preview can be found on my server https://kde.juliuskuenzel.eu/
My vision is to have this as a first step for (better) Craft documentation and later improve the documentation through the code comments as well as maybe move the docs form https://community.kde.org/Craft to here.
Do we want this at all? Any other thoughts? Consider this as a suggestion, I am open for any feedback!
Personally I can mostly see advantages of this. Only thing to keep in mind is, that this is no public API similar to eg. the frameworks. Craft is different in many aspects, but hence I think huge parts are interesting to the public (ie. craft users, blueprint authors,...) and not only Craft developers.
Note: to complete this we need to add the repository to https://invent.kde.org/sysadmin/binary-factory-tooling/-/blob/master/apidocs/repos-to-process after this is merged.