Add package to environment.systemPackages, services.dbus.packages, create gnome-remote-desktop user and group (fixes for GNOME 46)
This adds the `g-r-d` package to environment.systemPackages (allowing the usage of the `grdctl` command along with enabling `g-r-d`'s polkit rule), makes its dbus-related files recognizable to dbus, and creates the `gnome-remote-desktop` user and group necessary for systemd's running of the `gnome-remote-desktop-daemon` with the `--system` subcommand and enabling Remote Login.
33cafd77e7