Automatically feature "Transcriptions of the Week"

[TimJentzsch]

Every week, Buttercup should automatically determine the top 3 transcriptions of the week.
They should be determined by going through all the transcriptions of the week and fetching their Reddit upvotes.
The transcriptions with the most upvotes get featured.

The week that is featured should be delayed to the current week, such that the upvotes can stabilize.

This feature poses several challenges:

• Fetching all the transcription and their upvotes would take a substantial amount of time (minutes, probably), so it must be non-blocking
• The date of the next week must be persisted, such that the intervals still match after the bot has been restarted
• We need a good way to present the chosen transcriptions
• Upvotes != transcription quality