js: Add support for parental controls filtering to the desktop

Filter the apps shown on the desktop and in search results according to
whether they are blacklisted by the user’s parental controls.

This supports dynamically updating the filter during the user’s session.

This adds an optional dependency on libmalcontent. If that’s unavailable, no
parental controls filtering will occur.

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

GNOME/gnome-shell!465
4 jobs for !465 with parental-controls in 16 minutes and 33 seconds (queued for 1 second)
latest detached
Status Job ID Name Coverage
  Review
passed #328296
check_commit_log

00:00:38

 
  Build
passed #328297
build

00:14:10

 
  Test
passed #328298
test

00:01:44

passed #328299
test-pot

00:00:53