AVRCP: Use MediaController

RemoteController has been depreciated since M.
MediaController lets us track a lot more things and update data as the
state of audio changes.  We track and log some of these changes for bug
followup.

This also should fix some bugs related to metadata display not happening
on startup / track change / app change.

Bug: 27178384
Bug: 27745277
Bug: 26837775
Bug: 27534794
Bug: 27153373
Change-Id: I246d9641a5e921ed4434495f5c2dfac67d568952