Introduce PerDisplayInstanceRepository (and use it for SysUIState)

This allows to create display scoped instances elegantly, and is
supposed to replace PerDisplayStore. This cl is not aimed at refactoring
all the code using PerDisplayStore (it will happen in a follow up).

SysUIState is now only provided by the repository, and cached until
displays are removed.

Bug: 362719719
Bug: 398011576
Test: SysUiStateTest, PerDisplayInstanceRepositoryImplTest
Flag: com.android.systemui.shade_window_goes_around
Change-Id: I3d8a8ae4cfc54014772f8831b386bc6aadf2fa96