Better Leaderboards

[Greenfoot5]

Currently, leaderboards use exploitavoid.com, but this has several issues (not all on exploitavoid, some on our implementation):

• Secrets are easily found
• No global leaderboard with totals from all levels
• No local score saving
• Two players using the same name doesn't work (and players can't change their name so if they pick someone else's there's no check)
• It's a pain to reset the scoreboards each update
• There's no metadata (no version, no leaderboard customisation, etc.)

One possible fix would be to setup our own server, using https://github.com/Dino0040/Leaderboards/tree/v1.0.2 as the base, and then expand, allowing metadata (which can be used for customisation, version and players of the same name), allow deleting of the player's data, better login systems, a global leaderboard and more.

This one would be a big update, and if taken up by someone other than me, you'd have to work closely with me and account for data privacy (allowing players to opt-out at any point of sharing their names on the leaderboards, as well as the privacy policy and terms of service updates)

[Greenfoot5]

With the creation of #125 I'd like this to focus more on anything that requires an update to the server. This excludes:

• No local score saving from the above

Everything else is within scope as it requires some sort of change relating to the server.