[2021] Inventory changes

Hallooo! I feel summoned! No ETA on this. It requires some really delicate engineering to run the fix (which wouldn't require a patch I don't think, it's more a refactoring of how things are stored on this side).

We can remove deeds on request by the way, and soon we will have a regular automated operation that will clear out duplicate cosmetics automatically, we just need to solve a few issues with the Steam item server introduced in 4.3.