Add the dmenu-rs-enable-plugins package.
The dmenu-rs-enable-plugins package is identical the dmenu-rs, except
that it is built with all plugins available in the dmenu-rs respository
(whereas the dmenu-rs package is built with none). The same underlying
derivation is use, except a boolean flag is passed to indicate whether
or not to enable plugins.
See https://github.com/NixOS/nixpkgs/issues/333733
and https://github.com/Shizcow/dmenu-rs
