Serializing all event handling from SystemUI

> EventQueue is only accessed on the binder thread
> For every new touch down, we use a new event queue to prevent race conditions
> All event hendling are serialized by event queue (including quick switch/scrub)
> Using state handlers for quick scrub

Bug: 73356768
Change-Id: Idde33a348270b8167a087129f177d5d2b54f5822