Enhancement for group operation in output switcher

-Add new group components in xml layout and assets
-Adjust view objects in adapter for new layout
-Add aboveStatusbar in MediaOutputControllter to keep the dialog style
when switching
-Add getGroupMediaDevices() in MediaOutputController to provide available
device list for group operation
-Update test cases

Bug: 155822415
Test: atest MediaOutputAdapterTest MediaOutputControllerTest MediaOutputBaseDialogTest MediaOutputDialogTest
Change-Id: If74bf2efb89a8ece61f4e0cf13e4dcfa30cb0a8a