OMS: teach the OMS about static RROs

Teach the OMS about static RROs (those with <overlay isStatic="true">)
and add a new OVERLAY_ENABLED_STATIC state to OverlayInfo. This makes
isStatic less of an edge case and something that can be reasoned about
together with the other states.

Bug: 78809704
Test: atest OverlayHostTests OverlayDeviceTests
Change-Id: Ia785554ed2bcf7679888c3ccdaeaedca1430a477
4 files changed