Core/Creatures: Implement StringId for Creatures, a custom identifier to make finding specific creatures in script easier

Port From (https://github.com/TrinityCore/TrinityCore/commit/61c51b76c00d932a9180bc6781a244dc18375ef7)

Source/Game/Entities/Creature/Creature.Fields.cs

@@ -27,6 +27,9 @@ namespace Game.Entities
         CreatureTemplate m_creatureInfo;
         CreatureData m_creatureData;
 
+        string[] m_stringIds = new string[3];
+        string m_scriptStringId;
+
         SpellFocusInfo _spellFocusInfo;
 
         long _lastDamagedTime; // Part of Evade mechanics

Source/Game/Entities/Creature/Creature.cs

@@ -433,6 +433,8 @@ namespace Game.Entities
             //We must update last scriptId or it looks like we reloaded a script, breaking some things such as gossip temporarily
             LastUsedScriptID = GetScriptId();
 
+            m_stringIds[0] = cInfo.StringId;
+
             return true;
         }
 
@@ -2759,6 +2761,27 @@ namespace Game.Entities
             return Global.ObjectMgr.GetCreatureTemplate(GetEntry()) != null ? Global.ObjectMgr.GetCreatureTemplate(GetEntry()).ScriptID : 0;
         }
 
+        public bool HasStringId(string id)
+        {
+            return m_stringIds.Contains(id);
+        }
+
+        void SetScriptStringId(string id)
+        {
+            if (!id.IsEmpty())
+            {
+                m_scriptStringId = id;
+                m_stringIds[2] = m_scriptStringId;
+            }
+            else
+            {
+                m_scriptStringId = null;
+                m_stringIds[2] = null;
+            }
+        }
+
+        public string[] GetStringIds() { return m_stringIds; }
+        
         public VendorItemData GetVendorItems()
         {
             return Global.ObjectMgr.GetNpcVendorItemList(GetEntry());
@@ -3293,6 +3316,8 @@ namespace Game.Entities
             // checked at creature_template loading
             DefaultMovementType = (MovementGeneratorType)data.movementType;
 
+            m_stringIds[1] = data.StringId;
+
             if (addToMap && !GetMap().AddToMap(this))
                 return false;
             return true;

Source/Game/Entities/Creature/CreatureData.cs

@@ -92,6 +92,7 @@ namespace Game.Entities
         public uint SpellSchoolImmuneMask;
         public CreatureFlagsExtra FlagsExtra;
         public uint ScriptID;
+        public string StringId;
 
         public QueryCreatureResponse QueryData;