Moves filmcraft-mxf (storytold/filmcraft@4bec22b) into craft_media::mxf.
ByteSource is the crate's trait, Codec::codec_id() and
EssenceTrack::codec_params() map tracks to CodecId, and the writer names
craft-media as company and product unless the caller sets them.
Fixes two panics: EssenceTrack::sync_before on a track without picture
samples, and Timecode::format for a drop-frame start near i64::MAX.
Adds Container::Mxf, an ffprobe/ffmpeg oracle test for the reader and the
writer, and hostile-input tests.
Dylan M. Taylor
d3bc790aba