[DO NOT MERGE] Transitions: LOCKSCREEN->DREAMING

Add general support for lockscren->occluded/dreaming transitions,
including improved support for camera gesture occlusion. Double-tap
power will send various signals, so capture the double-tap as soon as
possible to cancel a transition in favor of the occlusion transition.

For LOCKSCREEN->DREAMING only, delay call to setOccluded, as it causes
jank when done too early. Also absorb touches while this transition is
running to prevent strange artifacts from popping in if the display is
touched.

Test: atest KeyguardRepositoryImplTest
KeyguardTransitionRepositoryTest
NotificationShadeWindowViewControllerTest
LockscreenToDreamingTransitionViewModelTest
LockscreenToOccludedTransitionViewModelTest
NotificationShadeWindowViewTest NotificationPanelViewControllerTest
Bug: 260637747

Change-Id: Ie2593706f2848ca715e557c8d4dfc129d93a29f1