Select existing order when creating an order from instance record

Purpose: The FOLIO system support the possibility to create orders in other modules then the Order app, in order for institutions to work efficiently. This story is about creating of an order from Inventory, and more specific the instance record.

Use case:
There are multiple request for a given instance record, and as an acquisition manager, I decide to buy an extra copy/copies, to get the request queue, and the patrons waiting time down.

Stories:

1. Display modal
   • Given is viewing instance
   • When user has clicked "New order" in instance action menu
   • Then Create order modal is displayed
   • AND message is shown: "Selecting an existing order before clicking Create", will add a new order
     line to the selected order for this title. Leaving the order number field
     blank and clicking "Create" will allow you to create a new purchase order
     and purchase order line for this title."
2. Add to existing PO
   • Given user is creating order from instance
   • When Create order modal is displayed
   • Then user can input an existing PO number
   • AND click Create to use that existing PO
3. Create new PO
   • Given user is creating order from instance
   • When Create order modal is displayed
   • Then user does NOT input an existing PO number
   • AND click create to create a new PO
4. Validate PO number
   • Given Create order modal is displayed
   • When user inputs a PO number and deselects input box
   • Then validate that the PO number added exists
   • AND if not display message: "Po number does not exist"

Note: for this release it might need to be a manual input as we missed the deadline for adding new modules (Ie. ui-plugin-find-order likely can not be added until Nolana release)