Frameworks: add never sleep screen mode (1/2)

to qs ScreenTimer Tile
to PW ScreenTimer toggle
as general option as well

Change-Id: Ic78356c1b96044562efbce3cb0d0d5c93d773a19
Signed-off-by: scott <scott@ubuntu.com>
Signed-off-by: scott <scott@ubuntu>

Conflicts:
	packages/SystemUI/res/values/slim_strings.xml

Conflicts:
	packages/SystemUI/res/values/strings.xml
	packages/SystemUI/src/com/android/systemui/quicksettings/ScreenTimeoutTile.java
	packages/SystemUI/src/com/android/systemui/statusbar/powerwidget/ScreenTimeoutButton.java