Refactor item handling.

Currently all items in your inventory is spawned in the world at 0,0,0 which contributes to the entity limit. We should find a way to only spawn the items that are being used and make the items in the inventory just be data instead of being spawned entities, this would probably allow players to have a lot more items in their inventory and save up on used entity limit. The galat chest items are not handled this way though.

We should also investigate a way to convert string names of items to some kind of short hand like an ID and way to convert them back to script name so players won't loose any items by us changing the script name.

No files, tests, or entry points are named. Start by tracing how inventory items and galat chest items are spawned, then review how item script names are stored and converted. Done means inventory items remain data rather than spawned entities, while item names can be safely converted and restored without loss.