Some cleanup in RecentsView

> Merging overview and all-apps scrims into a single View
> Decoupling TaskMenuView from taskView

Bug: 184676497
Test: Manual

Change-Id: I49f7249eaa2a800054385ab8e73a441d6a1b5e16

src/com/android/launcher3/states/SpringLoadedState.java

@@ -88,7 +88,7 @@ public class SpringLoadedState extends LauncherState {
     }
 
     @Override
-    public float getWorkspaceScrimAlpha(Launcher launcher) {
+    public float getWorkspaceBackgroundAlpha(Launcher launcher) {
         return 0.3f;
     }