LLS: Load title and summary from ext. package if avail.

Query for packages that support the
ACTION_OPEN_LIVE_LOCK_SCREEN_SETTINGS and load the title and summary
for the preference from that package.

If no other packages exist or we are unable to load the title AND
summary, then we use the defaults and carry on as usual.

Change-Id: Ibbd5347aa35994877fa067b29cacbe9a9ed12dad
TICKET: CYNGNOS-2696
(cherry picked from commit eb595354)