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