Add an unlock screen to the application, which is shown on startup if
the current user doesn’t have permission to view the parental controls
of other users. It requests permission using a new polkit action which
implies the various accounts-service actions we need.
This adds a dependency on `polkit-gobject-1`.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Philip Withnall