[Exploit/Dupe] Container item (#26689)

* Core/Item: Fixed possible dupe with container items containing non unique non stackable items

* Fixed build

* Update sql script and related base structure

Co-authored-by: jackpoz <giacomopoz@gmail.com>
(cherry picked from commit d1e913162e)

sql/updates/characters/master/2022_03_11_00_characters_2021_07_18_00_characters.sql

@@ -0,0 +1,2 @@
+--
+ALTER TABLE `item_loot_items` ADD COLUMN `item_index` int(10) unsigned NOT NULL DEFAULT '0' AFTER `item_count`;