[DO NOT MERGE] Coordinated DREAMING->LOCKSCREEN animation

Part 1: Update dream side. Shift to utilize
KeyguardTransitionRepository as the source for all motion between
states. DreamingToLockscreenTransitionViewModel contains all logic
that subdivides the total animation time into flowables that emit
events during only their proper subsection. This means one animator
now runs the view animations across all spaces.

As part of this, add DreamCallbackController as a data source for
KeyguardRepository. The dream activity will signal the transition to
begin via onWakeUp(), which will start the view motions, then run the
unocclude transition, and then finally the lockscreen view motions.

Part 2 coming next... lockscreen tweaks

Test: atest KeyguardRepositoryImplTest
DreamOverlayContainerViewControllerTest
DreamOverlayAnimationsControllerTest
DreamingToLockscreenTransitionViewModelTest DreamOverlayServiceTest
Bug: 260631205

Change-Id: I9bcf877927d1e92e8c751d0b83d2dd70f15912f1