Battlefields: Move BF scripts out of game

Port From (https://github.com/TrinityCore/TrinityCore/commit/49523a74a4c28e5ae17f9a8352aa8224b765b7d8)

Source/Game/Scripting/ScriptManager.cs

@@ -18,6 +18,7 @@
 using Framework.Constants;
 using Framework.Database;
 using Game.AI;
+using Game.BattleFields;
 using Game.BattleGrounds;
 using Game.Chat;
 using Game.Conditions;
@@ -711,6 +712,12 @@ namespace Game.Scripting
             return RunScriptRet<AreaTriggerScript>(p => entered ? p.OnTrigger(player, trigger) : p.OnExit(player, trigger), Global.ObjectMgr.GetAreaTriggerScriptId(trigger.Id));
         }
 
+        //BattlefieldScript
+        public BattleField CreateBattlefield(uint scriptId)
+        {
+            return RunScriptRet<BattlefieldScript, BattleField>(p => p.GetBattlefield(), scriptId, null);
+        }
+
         //BattlegroundScript
         public Battleground CreateBattleground(BattlegroundTypeId typeId)
         {