Traveler's Backpack

✨ Added render types to the backpacks' model JSON to support custom models
✨ Added config option to prevent multiple players from accessing the backpack simultaneously
✨ Added a swap backpack feature that allows changing the currently equipped backpack without needing to unequip it first
🐛 Fixed duplication bug
🐛 Items can now be removed from upgrades' filter slots only by left-clicking, to prevent duplication bugs with items that allow right-click interactions