Update list of libraries

[penelopeysm]

Firstly, the list of repos is clearly incomplete: https://turinglang.org/library/.

Also, I think it would be good if we have libraries grouped into categories with links to both the GitHub repo as well as the API docs. Something like a table would be good, with columns for library name, description, GitHub, docs.

Now that TuringLang/Turing.jl#2347 is merged, I think I don't have any more immediate changes to make to other packages' docs, so it's a good time to do this.

Tentatively assigning myself but if anyone wants to take this on just ping me.