Set up ERM permissions model

Distinguishing 3 types of role:

• User (eg, Librarian) (View permissions for license/agreement)
• Manager (eg, eResource Manager) (Create, Edit and View permissions for license/agreement)
• Administrator (system administrator) (Create, Edit and View permissions, plus system capabilities)

Admin has all Manager and User privileges, and Manager has all User privileges.

Assumed:

• if you can access ERM, you can view the content that is in there (ie, all data for resources, agreements and licenses is viewable to all users). There are some recent stories that explicitly suppress content in certain situations (though that would apply to all users, so is not role-based so much as context-based; eg, ERM-108).

The current known permissions / capabilities are defined in https://docs.google.com/spreadsheets/d/1-uyPRkdfByaXUb9ceOPu3lotIwItJdCk8EyhYrEv4Qs/edit?usp=sharing.