[FEATURE] - Allow new entries in 03system/ITEM to be injected at a position rather than being tacked in the end.

[TopazTK]

This feature request is made because the item sorting in the inventory works by the order of the 03system/ITEM file. Allowing an item to be injected at say, after the Keyblades for example instead of the dead end of the file may allow for seamless additions.

[TopazTK]

Come on guys don't make ME write this one, I really don't wanna.