Fix wrong scaling of QS tiles

Also increase margin with the number of tiles shown
and tweak sizes for better usability

PS2: Whitespace fix

Change-Id: I78a1e0d41d487ac48edc5f8992b7d5c95fbbfa71
SystemUI : RemoteDisplayTile use executor

The registering/updating causes jank when done on main thread.

Change-Id: I3a07ddeeddf480641a8b1f55684983b24cd693d1