composer: add API to control display idle timer

Add new functions to control display idle timer
- Adding an API to r configure display idle timer.
- Extend DisplayCapability to query display support idle timer.
- Adding an callback for notify client the display is idle, the refresh
  rate changed to a lower setting to preserve power and vsync cadence
  changed. The client can enable vsync callback to learn the new vsync
  cadence before sending a new frame.

Bug: 194068871
Bug: 198808492
Test: build, vts
Change-Id: I47649d222022922926a05f2d700ca798f8f48b35