Add support for date type when editing terms in license settings

Purpose:
Support for setting a license term/custom property to have type 'date' in the license settings

User story statement(s):

As an ERM librarian
I want to add a new license term with type = date
so that I can record terms that are expressed as dates

Scenarios:

1. Scenario:
   • Given the license settings -> terms
   • When I add a new term and click the 'type' dropdown
   • Then I see the option to use 'date'
2. Scenario:
   • Given I have selected 'date' as the term type
   • When I save the term
   • Then it has a type of date