refactor utils monolith

[Rich Trott]

[Rich Trott]

Stuff seems to fall into a few categories, although there may be some overlap.

• One genuine utility function
  • promiseUntil()
• Rendering helpers that should probably ultimately end up inserted via binding in a web component
  • anchorFromMid()
  • trackAnchor()
  • artistAnchors()
  • releaseAnchor()
• Playlist helpers
  • mergeArtistsAndContributors()
  • pickContributor
• Video helpers
  • searchForVideoFromTrackDetails()
  • extractVideoId()
  • wrapVideo()