Create ffmpeg bindings for go

[djthorpe]

Finish the first draft of the ffmpeg bindings for a modern ffmpeg version. Specifically, audio sample conversion would be great. Make against version 6.1

Repo: https://github.com/mutablelogic/go-media

FFMPeg examples to create:

• [ ] avio_http_serve_files.c
• [ ] avio_list_dir.c
• [ ] avio_read_callback.c
• [x] decode_audio.c
• [ ] decode_filter_audio.c
• [ ] decode_filter_video.c
• [x] decode_video.c
• [x] demux_decode.c
• [x] encode_audio.c
• [x] encode_video.c
• [ ] extract_mvs.c
• [ ] ffhash.c
• [ ] filter_audio.c
• [ ] hw_decode.c
• [ ] mux.c
• [ ] qsv_decode.c
• [ ] qsv_transcode.c
• [x] remux.c
• [x] resample_audio.c
• [x] scale_video.c
• [x] show_metadata.c
• [ ] transcode.c
• [ ] transcode_aac.c
• [ ] vaapi_encode.c
• [ ] vaapi_transcode.c