[Bug] Item Purchase Offset when multiple buyers are buying at the same time. (#4628)

* [Bug] Item Purchase Offset when multiple buyers are buying at the same time.

- Much of the code lifted from TAKP/P2002 and adapted
- Needs Testing
- This should help prevent situations where multiple people are purchasing items from a merchant and both attempt to purchase the same temp merchant or limited item, it should result in the later person recieving a notice that the item no longer exists and refreshes the merchant table.
- Updated strings

* fix formatting

* Push

* Update client.cpp

* Update database_update_manifest.cpp

* Update database_update_manifest.cpp

* Update database_update_manifest.cpp

* Update client.cpp

---------

Co-authored-by: Kinglykrab <kinglykrab@gmail.com>
Co-authored-by: Akkadius <akkadius1@gmail.com>

zone/entity.h

@@ -578,6 +578,9 @@ public:
 
 	int MovePlayerCorpsesToGraveyard(bool force_move_from_instance = false);
 
+	void SendMerchantEnd(Mob* merchant);
+	void SendMerchantInventory(Mob* m, int32 slot_id = -1, bool is_delete = false);
+
 protected:
 	friend class Zone;
 	void	Depop(bool StartSpawnTimer = false);