Improve package parsing for transcoding

To avoid hard-coding large strings in actual code and avoid
conflicting server/system_server device config settings, we now store
the transcode_compat_manifest as a raw resource file in MediaProvider.

Additionally, we avoid parsing the compat manifest if transcoding is
disabled, this allows us turn off transcoding and reduce side
effects.

Lastly, device config manifest values are upated on transcode enabled
switches

Bug: 174161238
Test: atest TranscodeTest

Change-Id: Iafff3eb7841b2c28a91e59853e7e365cd7facb57
3 files changed