[gui] fix setting state on controls inside groups inside containers. fixes #14295
[smartplaylist] fix incorrect field used for Studio/MPAA fields for episodes. fixes #14875
[depends] move ffmpeg to unified deps
[configure] remove internal ffmpeg
sq to configure - we need to be able to selectively disable hw codecs
sq to configure - get rid of USE_EXTERNAL_FFMPEG
remove ffmpeg from tree
ffmpeg: remove dll wrappers
add ffmpeg lock manager
todo: refactor to own file
ffmpeg: move callbacks into separate file