Unify the application id
Currently, GCC uses
org.gnome.ControlCenter
per https://gitlab.gnome.org/GNOME/gnome-control-center/blob/master/shell/cc-application.c#L288
org.gnome.Settings
per https://gitlab.gnome.org/GNOME/gnome-control-center/blob/master/shell/gnome-control-center.desktop.in.in#L4
The desktop file & the appdata file shipped with GCC still uses gnome-control-center
as a name. They should be updated to use the app-id instead.
Was going to prepare a MR to fix that, still not sure which app-id to go with.