Core/Creatures: Allow disabling loot for creatures

Port From (https://github.com/TrinityCore/TrinityCore/commit/ebf799c0f696ec88be66795d4ad0a20fa5ce5e92)

Source/Game/Entities/Creature/Creature.cs

@@ -1270,6 +1270,10 @@ namespace Game.Entities
         public void SetTapList(HashSet<ObjectGuid> tapList) { m_tapList = tapList; }
         public bool HasLootRecipient() { return !m_tapList.Empty(); }
 
+        public bool CanHaveLoot() { return !_staticFlags.HasFlag(CreatureStaticFlags.NoLoot); }
+
+        public void SetCanHaveLoot(bool canHaveLoot) { _staticFlags.ApplyFlag(CreatureStaticFlags.NoLoot, !canHaveLoot); }
+        
         public void SaveToDB()
         {
             // this should only be used when the creature has already been loaded

Source/Game/Entities/Unit/Unit.Combat.cs

@@ -703,6 +703,9 @@ namespace Game.Entities
                     if (tapper != null)
                         tappers.Add(tapper);
                 }
+
+                if (!creature.CanHaveLoot())
+                    isRewardAllowed = false;
             }
 
             // Exploit fix
@@ -900,7 +903,7 @@ namespace Game.Entities
                     else
                         creature.AllLootRemovedFromCorpse();
 
-                    if (LootStorage.Skinning.HaveLootFor(creature.GetCreatureTemplate().SkinLootId))
+                    if (creature.CanHaveLoot() && LootStorage.Skinning.HaveLootFor(creature.GetCreatureTemplate().SkinLootId))
                     {
                         creature.SetDynamicFlag(UnitDynFlags.CanSkin);
                         creature.SetUnitFlag(UnitFlags.Skinnable);

Source/Game/Spells/SpellInfo.cs

@@ -1034,7 +1034,7 @@ namespace Game.Spells
                             if (targetCreature == null)
                                 return SpellCastResult.BadTargets;
 
-                            if (!Loots.LootStorage.Pickpocketing.HaveLootFor(targetCreature.GetCreatureTemplate().PickPocketId))
+                            if (!targetCreature.CanHaveLoot() || !Loots.LootStorage.Pickpocketing.HaveLootFor(targetCreature.GetCreatureTemplate().PickPocketId))
                                 return SpellCastResult.TargetNoPockets;
                         }