Rewrite leaderboard to remove react-table-6

[UncleClapton]

react-table-6 will soon become a React 18 upgrade blocker due to it's use of UNSAFE_ methods.

We need to investigate paths forward.

• Upgrade to react-table v7
  • Is an option, but it is drastically different and would require a rewrite from scratch anyway.
  • Further, v7 tends to lead to some somewhat ugly code that I would rather want to avoid, and we need to bring our own UI. from scratch
• Finding another table component
  • Not sure if we want to lock ourselves into another component like this again?
• Rewrite from scratch with a custom brewed component for listing
  • Would give us reason to abstract some pagination logic from blogs for other purposes.
  • Full stylistic control would be a bonus