audio: Add AIDL definitions for Playback/RecordTrackMetadata

This is a temporary change for unblocking Bluetooth
audio AIDL development. When Audio AIDL gets
released officially, it should be overwritten.

Bug: 198812639
Test: m android.hardware.audio.common
Test: m check-vintf-all
Change-Id: Ia63135da4af4682e471e7de6b191b19e7a326a1e
Merged-In: I7064c3819d4c8e61981542ca2ccc52ca992a4ef8