[1/2] Base: Toggle lock screen camera widget

Adds an option to enable/disable camera widget on lockscreen.

Settings: https://gerrit.omnirom.org/#/c/4702/

Change-Id: Ia2ccdd306956cddd8285c30ccceb759dff406366
Signed-off-by: PipelinerArd <kristoferard@gmail.com>

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java