Implement more robust playlist selection

[Hakkin]

The current playlist selection is fairly basic, just matching the playlist group names, with a special "best" case that will select source quality if available, otherwise the highest bitrate playlist.

A more ideal playlist selection would be similar to the format selection youtube-dl provides, where you can filter by stream metadata (we already have this data available in code, we're just not using it), and allow fallback formats if the preferred one is not available.

Fallback playlists would be particularly useful for record.sh, since it can be difficult to guarantee a playlist group will exist across multiple streamers (besides source quality), in which case you could just specify something like 720p60/720p30/best, or [height=720]/best.