Simpler way to override or unregister items

[HashimTheArab]

Currently the only way to have a custom item is to only give that item to players, which works but the original item is still in the creative inventory.
Another method is to override it in HandleItemUse but thats not convenient.

I think the best solution would be a way to unregister items

[T14Raptor]

Duplicate of #221?

[Sandertv]

I've mentioned this before, I'm not a fan of replacing (let alone unregistering!) items and blocks. All dragonfly code assumes specific items and blocks exist and being able to remove items/blocks opens up a massive can of worms.