Add utility slot

Add a utility slot in the inventory, above the offhand slot which could store a new quiver item, working similar to the bundle but for just arrows. You could also put a shulker box in this slot to act as a backpack, adding an extra inventory tab for the items inside. To balance this, when wearing a shulker box, you would no longer be able to sprint. The utility slot could also be used to hold the elytra, allowing you to wear an elytra and a chestplate at the same time. However, this particular feature of the utility slot holding an elytra may be considered too OP. The utility slot could also hold the proposed crab claw item from the 2023 mob vote, allowing players to extend their reach.