LiveDisplaySettings: Inject into Settings via IA

 * Simply declare the activity-alias in the manifest and make use
   of the new information architecture for the Setting app to inject
   LiveDisplay settings into Display category.

 * Set intent priority to -2, so that the preference is placed
   two positions bellow top one (right bellow Adaptive Brightness).

Change-Id: Ia743eb198343f69b22771c78f24b4f32929c9143