Sophisticated Backpacks

Fixes

• Fixed backpacks to yet again automatically fill with loot when they are placed in world by something like a dispenser and hopper or pipe tries to extract items from them. Also added a bit of code that on backpack storage load cleans up nbt contents tied to uuid of any backpacks that were never opened by player and don't have any items in them (when backpacks fill with loot they also create a new uuid, but if these are only fully extracted and then discarded these empty records would just waste memory resources especially if this is done with automatic mob farm that produces a lot of backpack drops)