Add OverviewScrim to show below overview but above workspace

- Refactor some basic scrim logic to Scrim class and have
  WorkspaceAndHotseatScrim and OverviewScrim extend it
- Draw OverviewScrim under recents unless predictions are disabled, in
  which case draw it under hotseat (since that is in recents)
- Remove sysui scrim (behind status bar and nav bar) when overview is
  peeking

Bug: 132455160
Change-Id: Ia5d6f54582a4c5a70e3b2d4a98281567edd68519

src/com/android/launcher3/touch/AbstractStateChangeTouchController.java

@@ -518,6 +518,7 @@ public abstract class AbstractStateChangeTouchController
             logReachedState(logAction, targetState);
         }
         mLauncher.getStateManager().goToState(targetState, false /* animated */);
+        mLauncher.getDragLayer().getScrim().animateToSysuiMultiplier(1, 0, 0);
     }
 
     private void logReachedState(int logAction, LauncherState targetState) {