WIP: ancillary: pass through decoders and packetizers

On top of !7072

• Added ancillary passthrough for all packetizers
• Added vlc_ancillary_queue: a helper for asynchronous decoders that can't have a context (like MediaCodec)
• Implemented ancillary passthrough in avcodec via frame_info
• Implemented simple ancillary passthrough in faad.c (lot of decoders modules will be alike)
• Implemented ancillary passthrough in mediacodec via vlc_ancillary_queue
• Implemented ancillary passthrough in videotoolbox via frame_info

WIP:

• Need to find a proper way to get rid of the timestamp_Fifo helper in MediaCodec, any idea @fcartegnie ?
• If you agree, I will forward ancillaries in all other decoders modules