Add metadata fields used when streaming in atvremote

[postlund]

What feature would you like?

Make it possible to set metadata used when streaming, e.g. artist and title.

Describe the solution you'd like

Something like this:

$ atvremote -s ip --metadata-artist "Rick Astley" --metadata-title "Never gonna give you up" stream_file=secret_song.mp3

Any other information to share?

No