constellation: Use ffmpeg to update thumbnails for video files

[lgmarchi]

1. Use ffmpeg to update thumbnails for video files

You would add it in https://github.com/Satellite-im/Warp/blob/main/extensions/warp-ipfs/src/thumbnail.rs. A couple of things to note though is that you might want to make sure the target isnt a mobile platform and you should be able to execute the command using tokio process command vs std (since internally it would spawn the blocking thread)
and it might be worth putting ffmpeg behind a feature gate too