Create a builder for audio_util Metadata and migrate off bundles

The Util class in audio_util provides several static utilties for
converting between media framework objects and AVRCP flavored objects.
These conversion methods utilize bundles to do the translations, which
can be limiting when using non-parcelable objects.

While I would love to move off of AVRCP flavored objects for this
generic audio/media interface, that's going to be a meaty change thats
best done when a new version of the media framework is locked in and
supports everything we need. This change serves to make what we have
more flexible in the meantime.

Tag: #refactor
Bug: 153076316
Test: atest BluetoothInstrumentationTests
Change-Id: I0f29291cc4e8c92836bd1777c30dee184ac1b4e8