Move all transition queueing into transitioncontroller

This includes legacy syncs too. This way it's easier to
coordinate between transitions and syncs. It also makes
it possible to deal with concurrent transitions.

Bug: 276755325
Bug: 277838915
Test: atest TransitionTests
Test: existing tests should pass, this CL, alone, should be
      a no-op.
Change-Id: I0ce12bd2926c5cb4e17f1b9458c4658504675428