Add a "privileged_user" meson variable ("sudo" vs "wheel")
It is because different packaging can take use of it instead of carrying a patch for "sudo" vs "wheel" group names like in debian : https://salsa.debian.org/gnome-team/gnome-control-center/blob/debian/master/debian/patches/07_polkit_wheel_sudo_group.patch
Edited by Andre Klapper