Introducing DisplayPowerProximityStateController

This is a part of restructuring the way display service
updates the power state of the system. All the proximity related logic
has been abstracted out to a new class. As an attempt to keep this
simple and contained, no new logic has been added.

Bug: 241308364
Test: atest com.android.server.display
Change-Id: I45bb8cff3f6da805a816a9c3eef7428e7f7fbf7d