Add active display to ChameleonOS [2/2]

PS2:
Add pocket mode option, available if the device has
a proximity sensor.

PS3:
Add option to include ongoing and non-clearable notifications.

PS4:
Allow brightness control from 0% to 100%

PS5:
Refactor for release

Change-Id: Iae55640a31df68542c2af5d95097811b8fb1f66f