Core/Vmaps: Optimize loading vmaps

Port From (https://github.com/TrinityCore/TrinityCore/commit/35a2d49971984bcab96ac64fc52b30a9a4e06ce3)

Source/Game/Collision/Models/GameObjectModel.cs

@@ -78,7 +78,6 @@ namespace Game.Collision
             return !iModel.IsM2();
         }
 
-
         public override bool IntersectRay(Ray ray, ref float maxDist, bool stopAtFirstHit, PhaseShift phaseShift, ModelIgnoreFlags ignoreFlags)
         {
             if (!IsCollisionEnabled() || !owner.IsSpawned())

Source/Game/Collision/Models/ModelInstance.cs

@@ -74,6 +74,7 @@ namespace Game.Collision
         Matrix4x4 iInvRot;
         float iInvScale;
         WorldModel iModel;
+        uint referencingTiles;
 
         public ModelInstance()
         {
@@ -174,5 +175,10 @@ namespace Game.Collision
         }
 
         public void SetUnloaded() { iModel = null; }
+
+        public WorldModel GetWorldModel() { return iModel; }
+
+        public void AddTileReference() { ++referencingTiles; }
+        public uint RemoveTileReference() { return --referencingTiles; }
     }
 }

Source/Game/Collision/Models/WorldModel.cs

@@ -331,6 +331,7 @@ namespace Game.Collision
         uint RootWMOID;
         List<GroupModel> groupModels = new();
         BIH groupTree = new();
+        string name;    // valid only while model is held in VMapManager2::iLoadedModelFiles
 
         public override bool IntersectRay(Ray ray, ref float distance, bool stopAtFirstHit, ModelIgnoreFlags ignoreFlags)
         {
@@ -422,6 +423,9 @@ namespace Game.Collision
             return groupTree.ReadFromFile(reader);
         }
 
+        public string GetName() { return name; }
+        public void SetName(string newName) { name = newName; }
+
         public bool IsM2() { return Flags.HasFlag(ModelFlags.IsM2); }
     }