Add support for content type property on Agreements

Purpose:
It is sometimes useful to be able to categorise agreements by the type of content in the agreement. While there are content types available on packages and resources, the users would like to be able to explicitly add a content type to the agreement.

This should be a delivered with:

• A new 'content type' property for the agreement which can contain one or more values

• A refdata category for agreement content type with a user editable list of ref data values (via agreement settings/pick list values)

• A search filter for content type in Agreements search & filter screen

  • This should be a set of check boxes as per the Package content type filter (multiple selections combine as OR)

User story statement(s):

As an ERM librarian
I want to be able to set one or more content types per agreement
so that I can retrieve agreements by content type and view the content type of an agreement when I see the agreement

Scenarios:

1. Scenario:

   • Given the Agreements app

   • When I edit an agreement

   • Then I see the option to add one or more content types using a multi-value property box

   • Then I see the option to add a content type using a similar approach to the "add alternative title"

   • The option should be above the "Alternative names" property

2. Scenario:

   • Given I'm editing an agreement

   • When there are already content types added

   • Then I see a trashcan icon next to each content type

3. Scenario:

   • Given the list of content types in an agreement edit view with trashcan icons

   • When I click the trashcan icon

   • Then the content type is removed from display

   • AND on saving the agreement the content type is removed from the list of content types

4. Scenario:

   • Given the Agreements app

   • When I view an agreement

   • Then I should see a "Content types" property for the agreement with a semicolon separated list of content types underneath the Description

5. Scenario:

   • Given the Agreements app

   • When I view search and filter

   • There should be an option to filter by Content type above the "Tags" filter. This should be a checkbox filter as per the Package content type filter (multiple selections combine as OR)