Add songs to the Southbacon playlist

[eroepken]

The bot should:

• watch for and support links from the following services by default:
  • Spotify
  • YouTube
  • Vimeo
  • Soundcloud
• attempt to add the song to the playlist and notify the room that it's been added, or
• if the song is already in the playlist, notify #music that it's already in the list.

Open question(s):

• [x] Should we also keep track of songs that are retired so we can make sure if a song that has been retired is attempted to be added again, we can vote on it or something?

Honestly, I don't think Google Play and Amazon are open enough to share links from their sites, but I could be wrong. We also never share music from those two places, so I don't think we need to add them now. If we have a need for them later, we can do that.

Additionally, I'm not sure if you can share specific sings from Pandora, but we never do, so I'm not sure if we should support Pandora.

If anyone has suggestions for other media sources or corrections on any of the things I mentioned above, please comment.

[eroepken]

We aren't currently able to reliably retire songs. See reason for closing #1.