Rewrite Inventory Handling
there are a LOT of weird inventory stuff going on in EssX.
Fixes #3810 Fixes #4248
maybe more inventory issues that I'm unable to find?
ready for review, needs testing with all commands/features that touch items.
Tested commands: /book, /clearinventory, /condense, /createkit, /enchant, /hat, /item, /itemlore, /itemname, /kit, /powertool, /repair, /sell, /setworth, /skull, /spawnnmob, /unlimited, /worth
Didn't test keep inventory policy or trade/enchant signs yet.
Looks good so far though, didn't find any issues with any commands.
Still haven't tested the things above, but assuming those are ok this PR looks good to me