OpenSL-based audio support for BootAnimation

Respects dnd settings for sound playback.
Basic implementation uses in-memory wavs as buffers.
audioplay::playClip should not be called before previous clip ends.
Updated FORMAT.md to reflect no more audio_conf.txt

Bug: 29055299
Change-Id: Ifc358d7c85f11b8b54ae6446c40643b87bc567f2
8 files changed