AVRCP Browsing refactor

Small refactor of AVRCP target browsing.
Current implementation doesn't follow the BT spec and is
load heavy on BT startup.

Features:

- Change the MediaBrowser connection to when a BT event is
requesting it. Connection is kept alive for 5 seconds in
order to prevent multiple connection/disconnection while
browsing.

- "Bluetooth player" has been removed, the list of
browsable players now contains all browsable players.

- Browsable player validation is now done by fetching
packages that both support browsing and audio playing.

- Package add/removal is now supported for browsed players
and the update is broadcasted.

- Overall stability of AVRCP browsing should be increased.

- Non-browsable players are also sent in getFolderItems
for MediaPlayerList. This should enable to select a non-
browsable player from the remote to play.

Bug: 319275147
Bug: 326492797
Bug: 332465445
Bug: 326132268
Bug: 304805334
Flag: com.android.bluetooth.flags.browsing_refactor
Test: atest BluetoothInstrumentationTests
Change-Id: I97eda027df1f6bf727832051cc2d55070378851f