Implement POST /inventory/items/move for moving items between holdings.
1) Send move request (it contains id of holding to which items should be moved and items ids).
2) Send GET items collection and populate collection of updated items (with new item.holdingsRecordId)
3) Update updated items and send asynchronously update request for each item.
4) Wait all responses, populate errors if some of request failed.
More detail can be found on page: Move Holdings and/or Items.
5) Return response to client.
1) POST /inventory/items/move is implemented
2) Unit tests with code coverage at least 80%