drop vendored mkdocs-awesome-pages-plugin

[phaer]

trafficstars

...as we have meanwhile upstreamed it and the vendored version doesn't work with the latest mkdocs while the one in nixpkgs has been fixed.

[phaer]

Going to revisit later on, can't see how I am holding it wrong atm:

❯ nix repl
Welcome to Nix 2.18.5. Type :? for help.

nix-repl> :lf .
Added 19 variables.

nix-repl> pkgs = import inputs.nixpkgs {}

nix-repl> pkgs.python3.pkgs.mkdocs-awesome-pages-plugin
«derivation /nix/store/rc2s85gf0y06j118ns0wgklb16hhr5li-python3.12-mkdocs-awesome-pages-plugin-2.9.3.drv»