but 768498: Second part of access control changes

* Enable django-grappelli enhancements for admin

* Initial admin dashboard using Grappelli

* Add team ownership field to Document, with migration

* Add links to manage access policies on wiki documents

* Add wiki.view_document permission to model

* Helper to build URLs for managing Teamwork Policies on an object

* Add Teamwork methods to Document model to support hierarchical
  permission inheritance

* Add "Manage Roles" link to user profiles
Merge pull request #1248 from lmorchard/768498-more-access-control

768498 more access control