Extended the A2DP codec abstraction API

 * Added new A2DP codec-independent API and updated/renamed existing API.
   - A2D_InitCodecConfig()
   - A2D_InitDefaultCodec()
   - A2D_SetCodec()
   - A2D_IsCodecSupported() -> A2D_IsSourceCodecSupported()
   - A2D_IsSinkCodecSupported()
   - A2D_BuildSrc2SinkConfig() - previously bta_av_build_src_cfg()
   - A2D_IsSinkCodecSupported() - previously
       bta_av_co_audio_sink_supports_config()
   - A2D_IsSourceCodecSupported() - previously
       bta_av_co_audio_media_supports_config()
   - A2D_IsPeerSourceCodecSupported()
   - A2D_GetDefaultConfigSbc() - to be deleted
   - A2D_CodecSepIndexStr()

 * Added the corresponding SBC-specific implementation and a placeholder
   for vendor implementation.

 * Added the corresponding unit tests

Also:
 * Added type tA2D_CODEC_SEP_INDEX and list each known codec (Source or Sink):
   A2D_CODEC_SEP_INDEX_*
 * Renamed BTIF_SV_AV_AA_SBC_INDEX -> A2D_CODEC_SEP_INDEX_SBC
 * Renamed BTIF_SV_AV_AA_SBC_SINK_INDEX -> A2D_CODEC_SEP_INDEX_SBC_SINK
 * Renamed BTA_AV_MAX_SEPS -> A2D_CODEC_SEP_INDEX_MAX
 * Renamed tA2D_CODEC -> tA2D_CODEC_TYPE
 * Renamed tBTIF_AV_MEDIA_FEEDINGS -> tA2D_AV_MEDIA_FEEDINGS
 * Renamed tBTIF_AV_CODEC_ID -> tA2D_AV_CODEC_ID (to be deleted)
 * Renamed BTIF_AV_CODEC_PCM -> tA2D_AV_CODEC_PCM (to be deleted)
 * Renamed BTIF_AV_CODEC_NONE -> tA2D_AV_CODEC_NONE (to be deleted)
 * tBTIF_AV_MEDIA_FEED_CFG_PCM -> tA2D_AV_MEDIA_FEED_CFG_PCM (to be
   deleted)
 * tBTIF_AV_MEDIA_FEED_CFG -> tA2D_AV_MEDIA_FEED_CFG (to be deleted)
 * Moved SBC codec-related configuration and capabilities from
   btif/co/bta_av_co.cc to stack/a2dp/a2d_sbc.c :
   - bta_av_co_sbc_caps -> a2d_sbc_caps
   - bta_av_co_sbc_sink_caps -> a2d_sbc_sink_caps
   - btif_av_sbc_default_config -> a2d_sbc_default_config
 * Replaced usage of BTIF_AV_SBC_DEFAULT_SAMP_FREQ with
   A2D_SBC_IE_SAMP_FREQ_44
 * Merged bta_av_sbc_cfg_matches_cap() and bta_av_sbc_cfg_in_cap()
   into A2D_CodecInfoMatchesCapabilitySbc()
 * Misc other fixes and cleanup: use tA2D_STATUS as appropriate, remove
   FUNC_TRACE(), etc.

Bug: 30958229
Change-Id: I35e224754041cdce479c87e57d8e2c8b3adc8edd