Just for consistency, make settings related stuff live under the
org.freedesktop.NetworkManager namespace, rather than its own
org.freedesktop.NetworkManagerSettings namespace. Renames are done for
DBus interface names, DBus object paths, and polkit actions.
Remove the org.freedesktop.NetworkManagerSystemSettings bus name and
have everybody talk to org.freedesktop.NetworkManager. Now that we have
a single settings service that's embedded in the main daemon, we don't
need separate names anymore.
