Philip Withnall authored Nov 26, 2018 and Richard Hughes committed Jan 25, 2019

As well as filtering installation of applications, parental controls
need to prevent launching banned applications which are already
installed on the system (perhaps for other users). While installation is
controlled through OARS ratings, launching is controlled via a
blacklist.

Add a new quirk to GsApp for apps which should not be launchable due to
violating the blacklist, and check for it on the details page.

It is up to vendor plugins to implement the policy to set this quirk on
apps.

Signed-off-by: Philip Withnall <withnall@endlessm.com>