Implement a leaderboard

[crkellen]

Please fill out this Issue template to the best of your ability!

Type of Issue

• This Issue is a Bug
• This Issue is a Feature Request
• This Issue is a Design Issue/Request

Hint: Design Issues or Requests are changes to existing features, not new ones.

Description of the Issue:

Show the top scoring players (player score = kills + objective points) for each team or in total.

Additional comments or information:

Either do a total ranking system of the top 10 players no matter their team affiliation, or do two top 10's one for each team.
Also show each team's score on the leaderboard.