Core/Spells: Implemented personal summons

* By default determined by summon property flag SUMMON_PROP_FLAG_PERSONAL_SPAWN

src/server/game/Entities/GameObject/GameObject.cpp

@@ -2500,7 +2500,7 @@ void GameObject::UpdateModelPosition()
 class GameObjectModelOwnerImpl : public GameObjectModelOwnerBase
 {
 public:
-    explicit GameObjectModelOwnerImpl(GameObject const* owner) : _owner(owner) { }
+    explicit GameObjectModelOwnerImpl(GameObject* owner) : _owner(owner) { }
 
     virtual bool IsSpawned() const override { return _owner->isSpawned(); }
     virtual uint32 GetDisplayId() const override { return _owner->GetDisplayId(); }
@@ -2511,7 +2511,7 @@ public:
     virtual void DebugVisualizeCorner(G3D::Vector3 const& corner) const override { _owner->SummonCreature(1, corner.x, corner.y, corner.z, 0, TEMPSUMMON_MANUAL_DESPAWN); }
 
 private:
-    GameObject const* _owner;
+    GameObject* _owner;
 };
 
 GameObjectModel* GameObject::CreateModel()