[T6] Add a multiplayer and zombies leaderboards.

  • Feature: Add a leaderboard for zombies and multiplayer
    Description: Make it similar to the treyarch leaderboards
    Motivation: This should be added to the client so people can compete with one another for top spots in various things (kills, wins, revives, etc.)

  • Project Moderator

    @radicalcaptain Would also like to add, possibly adding a web based version to view the leaderboards might be a nice touch.