Added Item Lists for Inventory, Stash and Cube

[d2inventory]

ItemInfo has a new field now (GUID), this is needed to identify removed items on update.

[Zutatensuppe]

looks good to me 🦄

maybe at a later point we can replace iterating through inventory multiple times with a single iteration, because we are interested in all items anyway

[d2inventory]

Yeah, I didn't put much effort into making the code good/nice.
As soon as I found the array containing the position of the items I was ready to rewrite it anyway.
But looks like getting a pointer to that array isn't that easy.