Delegate splash screen starting window to SystemUI(1/N)

Mirror PhoneWindowManager#addSplashScreen to StartingSurfaceDrawer,
which make WMShell able to draw the splash screen starting window.

- Use StartingSurfaceController#DEBUG_ENABLE_SHELL_DRAWER to switch
drawer when developing this feature.

- Temporarily put StartingSurfaceDrawer in ShellTaskOrganizer, the
drawer should be controlled by a controller which should be create
while porting ActivityRecord#addStartingWindow to Shell.

Ref doc: go/delegate_starting_window

Bug: 131727939
Test: atest AppWindowTokenTests WindowOrganizerTests ActivityStackTests
Test: atest WMShellTest ShellTaskOrganizerTests
StartingSurfaceDrawerTests
Test: check from winscope that the splash screen window can
attach to/detach from the ActivityRecord.

Change-Id: I6dfc9ff75807e2f9479149d14f219c91a6527393