Remove judging / hacks functionality

[epicfaace]

We don't need this functionality anymore, since we're using Gavel.

This would include the tabs "Hack Table", "Judge Table", "Judge Leaderboard", and "Bulk Import Hacks".

@theopolisme @MYKatz do you remember if we used this functionality at all in February? I don't remember doing so.

[MYKatz]

We did require users to submit their hack on submit.treehacks.com, but I don't think that overlaps with this. All the data on those tabs is from TH 2019 so I think it's safe to remove.