[2/3] FW AV: Audio Theme Support

From: https://gerrit.omnirom.org/#/c/5244/

Original commit message:

 On the Java side, Android has support for both a
 Video Record Start sound, and a different Video
 Record Stop sound. However, this part here only
 supports one video recording sound.
 We added support for RECORDING_STOP sound (by default,
 the same as RECORDING).

Change-Id: Ib5c1b3b76ff91518c7c7c6a0601a9e80a73ce4d1
Merge "[2/3] FW AV: Audio Theme Support" into pac-4.4