[RFC 82 - lib.experimental] is looking for shepherds

fare proposes that we create a directory lib/experimental for experimental code,
also available as lib.experimental and pkgs.lib.experimental. Such code is
available for limited use within select parts of nixpkgs, with the explicit
opt-in approval of their respective maintainers, but not for widespread use
in other parts of nixpkgs.

https://github.com/NixOS/rfcs/pull/82