Serve aw-server-rust docs somewhere

[xylix]

This would likely be helpful for anyone new wanting to get into the codebase / read how it works.

Maybe on https://activitywatch.readthedocs.io/ , maybe pubilsh releases as crates and have the docs on docs.rs . @johan-bjareholt do you have any opinion on this?

[johan-bjareholt]

Would be nice to push it as crates so it would be available on docs.rs, but I don't think that's a priority. Would be annoying to manually do it and adding it to the CI would be a lot of work, so we'll postpone it for now IMO.

A good way to document the transforms in the query language I find more important now.