Relink items between holdings or holdings between instances

Overview: Support relink of items between holdings, or holdings between instances. Use drag and drop similar to as implemented in the Request app.

Use cases:
We have two items for title A on shelf qc. We want to move one of these items to the Reference shelf. Since we are specifying location and call number on the holdings level, we need to create a new Reference shelf holding and relink the item to that holding.

Chalmers: The current workaround, while we are not able to relink records, is to delete the record we would want to relink and then create a new one with the correct link. This is pretty cumbersome, and we may lose transaction history when moving items around.