Color coded the server browser and added a filter for password protected games

This implements #4495 and applies the color code style from www.openra.net/games/ with a legend:

![image](https://cloud.githubusercontent.com/assets/756669/5157404/c3e91e68-7309-11e4-9c5c-22fa5eface1e.png)

Essentially a followup of https://github.com/OpenRA/OpenRA/pull/6983 whose game name + "(Password)" was a little too subtle and unpolished for my taste.
Is fine if you don't want to go out of your way to make accessibility better, but removing the (Password) label actively makes this worse.

:+1: with that reinstated.