Add Volume panel

Volume panel hosts each volume stream, including:
- Media volume
- Call Volume
- Ring volume
- Alarm volume

Change-Id: I1801d10d2304c57615e9499386c638c74ffcd7c3
Screenshot: https://screenshot.googleplex.com/m764j65ECto
Bug: 117804161
Test: Manual app
Test: robolectric

tests/robotests/src/com/android/settings/panel/PanelFragmentTest.java

@@ -61,7 +61,6 @@ public class PanelFragmentTest {
         mFakePanelContent = new FakePanelContent();
         doReturn(mFakePanelContent).when(mPanelFeatureProvider).getPanel(any(), any());
 
-
         ActivityController<FakeSettingsPanelActivity> activityController =
                 Robolectric.buildActivity(FakeSettingsPanelActivity.class);
         activityController.setup();