Replace youtube-dl with yt-dlp as an optional dependency for mpv

I think it’s a better idea to have yt-dlp as an optional dependency for mpv insted of youtube-dl. (Already read this thread too)

As a bit of a side note, does anyone know how I can make mpv use yt-dlp instead of youtube-dl to stream videos?

It already is as of mpv 1:0.34.0-2.