Allow apps to construct AudioPresentation object

Added a Builder class to gather necessary parameters
for creating an AudioPresentation object.

Unhidden two getters--getPresentationId/getProgramId to keep API
symmetry.

Bug: 63901775
Test: android.media.cts.AudioPresentationTest
      android.media.cts.AudioTrackTest#testSetPresentationDefaultTrack
Change-Id: I5f4878973fcfd5e79494d2f530776f096713ac5f