Refactor BadgedImageView to extend FrameLayout

BadgedImageView was extending ImageView and drew the badge icon on top of the bubble icon. This makes it difficult to animate the app icon among other things.
Refactored BadgedImageView to extend FrameLayout. Moved bubble icon and app icon into separate ImageView's that are added to the FrameLayout.

Bug: 162857077
Test: compared layout before and after the refactor
Test: enabled RTL layout, compared layout before and after the refactor
Change-Id: I18645549a156d7d78eacc223fca39657346e08dd