Core/Objects: implement internal heartbeat timer for WorldObjects

Port From (https://github.com/TrinityCore/TrinityCore/commit/bf9cd88cebf752ce8614fbac8a7c6d1f0de7fee8)

Source/Game/Entities/Object/WorldObject.cs

@@ -41,6 +41,8 @@ namespace Game.Entities
             m_objectData = new ObjectFieldData();
 
             m_staticFloorZ = MapConst.VMAPInvalidHeightValue;
+
+            _heartbeatTimer = SharedConst.HeartbeatInterval;
         }
 
         public virtual void Dispose()
@@ -992,8 +994,17 @@ namespace Game.Entities
         public virtual void Update(uint diff)
         {
             m_Events.Update(diff);
+
+            _heartbeatTimer -= TimeSpan.FromMilliseconds(diff);
+            while (_heartbeatTimer <= TimeSpan.Zero)
+            {
+                _heartbeatTimer += SharedConst.HeartbeatInterval;
+                Heartbeat();
+            }
         }
 
+        public virtual void Heartbeat() { }
+
         public void SetIsStoredInWorldObjectGridContainer(bool on)
         {
             if (!IsInWorld)
@@ -3859,6 +3870,8 @@ namespace Game.Entities
 
         SmoothPhasing _smoothPhasing;
 
+        TimeSpan _heartbeatTimer;
+
         public FlaggedArray32<StealthType> m_stealth = new(2);
         public FlaggedArray32<StealthType> m_stealthDetect = new(2);