feature: end-of-session stats for likes

[jackconwayiv]

• related issue: make it so falling off the end of a power hour resets song entry to first, resets state to show "Start" button, and opens stats modal

BACKEND

• given a songbook key, fetch all song_entries for that songbook with >0 likes.
  • also include the name of the user who requested that song_entry
  • also include the song details (at least title and artist)
  • also include a list of each like on that song_entry with the users who liked it
• sort these song_entries by number of likes, then annotate them with likes_count
• who got the most likes? ("thumbs cup" a crown? a rose?)
• who gave the most likes? ("cheerleader")
• who had the best ratio of song_entries to likes? ("batting 1000") (these names all need improving)
• XC: Requested songs most consistently (beg, mid, end)
• XC: Innovator, requested most NEW songs
• XC: Supporter, requested most songs from other users’ lists
• XC: I Know What I Like: requested most songs from their own list

FRONT END

• third tab for "Liked Songs" in stats modal
• red bar graph ranking most liked songs
• across the top, "medals" or some kind of call-outs for people who earned each of the awards above
• "Best Contributor: Johnny's requests got 27 likes!" or something

[jackconwayiv]

Adjacent to this issue, some other session-end stat ideas:

• Calculate runtime (difference between now and timestamp of first requested song, or when "start" was pressed?)
• XC: scatterplot/timeline of likes, requests, pauses, new members (x axis is time)?