SettingsProvider: Migrate STATS_COLLECTION to secure.

  Migrate STATS_COLLECTION to secure from system table while
  retaining the user preference. Moving it to secure allows us
  to do per-user settings.

Change-Id: Ia55fdd8c6db418c4eaebf17a54b765d25a878471
SystemUI: make long pressing recent switch to last app

With this patch, long pressing the recents key on the navigation bar
will attempt to switch to your last application in the activity stack
before the active one.

The user's current home launcher package is ignored as well as SystemUI (so that
RecentsActivity does not influence the behavior).

Change-Id: I38771e0fce16b55bb5186af47115b4e812cb60b0
Signed-off-by: Roman Birg <roman@cyngn.com>
Signed-off-by: Adnan Begovic <adnan@cyngn.com>
frameworks: allow last app action to be assigned to hardware keys

Also fix multi-user handling for 'switch to last app' and 'kill
foreground app' actions.

Change-Id: I1fb586d19b1198e6888b0f11e0a2813acf0bcd5b
Signed-off-by: Roman Birg <roman@cyngn.com>
Signed-off-by: Danny Baumann <dannybaumann@web.de>
Signed-off-by: Adnan Begovic <adnan@cyngn.com>