Motion for hub <-> edit mode transition

Fix lockscreen flashing when starting the edit mode activity and
transitioning from alternate_bouncer to gone state.
Add custom keys and animations for entering and exiting the edit
mode in sceneTransitions.
Add animations for the grid and toolbar in CommunalHub for edit mode.

Bug: b/325108777
Flag: com.android.systemui.communal_hub
Test: atest CommunalInteractorTest
Test: atest CommunalSceneInteractorTest
Test: atest CommunalEditModeViewModelTest
Test: atest FromAlternateBouncerTransitionInteractorTest
Test: manually enter or exit the edit mode
Change-Id: Idfe1297679085c46c18af9ad09d1dd4f6e2391b1