Add HDR-HBM support into framework.

Add a listener to know when HDR layers are present on displays
which support HBM.

Pass both HDR and SDR brightness requests from DPC to
SurfaceFlinger. Lots and lots of scaffolding for this.

Bug: 175321409
Bug: 175821789
Test: atest com.android.server.display
Test: Manually verify that brightness levels are correct when in high
      lux and HDR, low lux and HDR, and various luxes without HDR.
Change-Id: I530299455a7745fd57d44b1e8b20477674894e21