ffmpeg binaries, so we don't lose them
Required by some bizhawk versions
Linux build is taken from https://www.johnvansickle.com/ffmpeg/old-releases/ffmpeg-4.4.1-amd64-static.tar.xz
Windows build is taken from https://www.gyan.dev/ffmpeg/builds/packages/ffmpeg-4.4.1-essentials_build.7z
Recompressed to .7z until SharpCompress supports .tar.xz, also everything but ffmpeg is removed to reduce file size.