Ensure that all actions are compared to fixed point in time (ie. world update start)

Port From (https://github.com/TrinityCore/TrinityCore/commit/60663d1374beef3103f4787152654034fa4a8897)

Source/Game/Time/GameTime.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+public class GameTime
+{
+    static long StartTime = Time.UnixTime;
+
+    static long _gameTime = 0;
+    static uint _gameMSTime = 0;
+
+    static DateTime _gameTimeSystemPoint = DateTime.MinValue;
+    static DateTime _gameTimeSteadyPoint = DateTime.MinValue;
+
+    public static long GetStartTime()
+    {
+        return StartTime;
+    }
+
+    public static long GetGameTime()
+    {
+        return _gameTime;
+    }
+
+    public static uint GetGameTimeMS()
+    {
+        return _gameMSTime;
+    }
+
+    public static DateTime GetGameTimeSystemPoint()
+    {
+        return _gameTimeSystemPoint;
+    }
+
+    public static DateTime GetGameTimeSteadyPoint()
+    {
+        return _gameTimeSteadyPoint;
+    }
+
+    public static uint GetUptime()
+    {
+        return (uint)(_gameTime - StartTime);
+    }
+
+    public static void UpdateGameTimers()
+    {
+        _gameTime = Time.UnixTime;
+        _gameMSTime = Time.GetMSTime();
+        _gameTimeSystemPoint = DateTime.Now;
+        _gameTimeSteadyPoint = DateTime.Now;
+    }
+}