Allow the width of the notification panel to be adjusted separately from

the quick settings panel.

Also, introduce the option to allow the clipping that the panel by
default does to be disabled. This allows the items in the panel to be
swiped beyond the edges of the panel.

Test: booted up on AAE headunit and Angler device.
Change-Id: I8d8f501f98fea5c1c85541099df4ca34d10fc648