huge commit for advanced stats feature.

broke data out into its own library.
may be breaking changes with existing plugins

Plugins/Stats/Client/Abstractions/IServerDistributionCalculator.cs

@@ -0,0 +1,11 @@
+using System.Threading.Tasks;
+
+namespace Stats.Client.Abstractions
+{
+    public interface IServerDistributionCalculator
+    {
+        Task Initialize();
+        Task<double> GetZScoreForServer(long serverId, double value);
+        Task<double?> GetRatingForZScore(double? value);
+    }
+}