Implement a non-HLS transcoding option

[pedromsilvapt]

While HLS seems to be the most seamless option for enjoying transcoded media in formats that Chromecast does not natively support, it's reliability has left a little to be desired. As such, and as a fallback, we should implement a simpler, alternative transcoding format that writes to an mkv/mp4 container as a stream, saving it to the disk, all while serving the Chromecast stream as fast as possible.

Limitations

Since it is impossible to know the duration, or the indexes of where in the file each timestamp is until the file is finished, seeking does not work natively. A custom made alternative may be considered for this use-case.