Topgun 2 refactor and rewrite of leaderboard logic

[cdm]

• Revisit and review the original design and limitations with @SuDa2103
• Whiteboard and discuss improvements to the leaderboards/feature requests
• Begin implementing filter / sort approach and prepare for unit testing/alternative mux
• MVP single leaderboard with multiple general balance ranking
• Add unit tests to MVP leaderboard filters
• Add DB state management (leaderboards data is persisted, the leaderboards can recover from restarts?)
• Experiment with multiple leaderboards and prepare to launch from runtime e.g. config/DB
• Ensure high coverage of runtime launch and DB

[cdm]

[cdm]

Added whiteboards for reference @SuDa2103