Feat: add av1 support for smaller snapshots and videos

[BenediktBertsch]

Found out that the lib didnt support the AV1 format therefore I added it for myself.

With this you can create smaller images like this:

var source = FFProbe.Analyse(file.FullName);
var streamIndex = source.PrimaryVideoStream?.Index
                ?? source.VideoStreams.FirstOrDefault()?.Index
                ?? 0;
var args = FFMpegArguments
            .FromFileInput(file.FullName, false, options => options
            .Seek(TimeSpan.FromSeconds(source.Duration.TotalSeconds / 3)));
var opts = new Action<FFMpegArgumentOptions>(options => options.SelectStream((int)streamIndex, 0)
                                            .WithVideoCodec(VideoCodec.LibaomAv1)
                                            .WithFrameOutputCount(1)
                                            .Resize(null));
args.OutputToFile(name, false, opts).ProcessSynchronously();

This takes way longer but the size difference is huge for example: 1811KB in .png to 98KB in .avif

If there is anything missing to do like writing tests etc. just mention it. I havent seen any tests for the VideoCodec.Png therefore I didnt implement any tests yet.