Remove Application Widget from LockPatternUtils

The application widget option has been removed from Settings, and should
instead be handled by the application granted with the
SET_APPLICATION_WIDGET permission.

This change:
- removes the configuration value from the LockScreenSettings database; and
- removes the producers and consumers of the value.

Change-Id: Ia83e8d713d4455a9c898a8048a256afb7291af0b

Conflicts:

	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java
Properly handle movable recents clear-all button, in spite of adding it to a common container w/ the ProtectedApps button

Change-Id: Ie394385b7158d80d27465da9387288e75c19fdd0