Implement additional workflow for adding agreement lines to agreements

This is in addition to the existing options of adding agreement lines based on the contents of the 'basket' or from within eHoldings

Process:

• From agreement view pane new "Add agreement line" button
• This opens a new Agreement Line edit screen
• On the Agreement Line edit screen there should be new options displayed as a button group (only one selection valid at a time) to:
• Add resource from basket (do not show if tennant setting "Hide internal agreements knowledgebase" is TRUE)
• Add resource from eHoldings (only show if eHoldings installed)
• If there is only one valid option available to the user then they should not see the button group and the UI element to select a resource should be shown immediately

On selecting one of these options:

• a UI element should be shown which is different dependent on the option they have selected

If the user has selected "Basket" the UI element should provide the option for the user to select an item from the basket using the dropdown mechanism (the operation is the same as used in the Edit Agreement screen when adding an Agreement Line with changes to the field label, button text and addition of ghost text when the basket contains no e-resources).

If the user has selected "eHoldings" the UI element should allow the user to use the eHoldings find-package-title plugin to search and select an eHoldings title or package.

If the user is in the process of creating the agreement line, they should be able to remove a linked resource (from either source) and start the process again.

If the user is in the process of editing an existing agreement line, they should not have an option to remove or change the link to a resource - once an agreement line is linked to a resource they cannot change this (if they really need to remove the resource they will have to delete the agreement line and start with a new agreement line)

Once the user has completed their edits, they can click "Save and Close" to save the agreement line
A user must either link a resource, or fill out the Description (ERM-1003) before they can save and close the AL

Wireframes attached showing the display on the Agreement Line edit page for different scenarios