Add recent apps in app & notification

- Introduce a RecentAppsPreferenceControler, which queries
  UsageStatsManager and displays a list of recently used apps.

- Add a control flag for this feature, intially set to false.

- Make ManageApplications a static pref item instead of dynamic one.
  This makes the RecentAppController easier to control "See all"
  preference, which is backed by ManageApplications.

- Also adjust app_items.xml layout to make app item UI consistent with
  preference item.

Change-Id: I0b9e1784faed32b3055ebf96ef98b6a5e422de50
Fix: 33265548
Test: robotests