Update usernames in the database for accurate leaderboards

[EtherealMC-Bit]

Description of the feature
Minecraft let's you change your username frequently, and players like to make use of this. However the KP database does not update the username column when a player changes their username. This causes leaderboards made using the KP placeholders to become inaccurate with time.

How the feature is useful
No more players asking hey who is . Or <Why does the leaderboard say . Currently I have to manually edit the player's names in the database and this is a pain.