Problems with the last admin of a leaderboard deleting their account

[Eldemarkki]

If the last admin of a leaderboard deletes their account, the leaderboard will be left dangling in the database. Same error as #24

I can think of 2 possible solutions:

• After an admin deletes their account, it also deletes the leaderboard (but shows a notification “This will also delete leaderboards X, Y and Z. Are you sure?”)
• Don't allow the user to delete their account before they have promoted another admin or deleted the leaderboard
  • This is worse in my opinion, because users should be able to delete their data as easily as possible for data privacy/safety reasons