Merge organization logic into groups

[ross]

Requirements

Merge the organizations plugin into the core groups functionality. Most of this is templating and a small number of changes to the group controller.

Investigate the possibility of removing the Membership model and using FKs.

Interface

This is likely to consist of:

• Updating the templates in templates/group/

• Configuring whether we want to constrain datasets to a single group (as per organizations)

• Implementing the separate user management (add users to group).

• Checking the publisher auth to not necessarily rely on group type = 'organization'

• Making sure that the changes still work with publisher auth.

User Stories

None

Tasks

[ ] Code

[ ] Configuration

[ ] Model/Migration?

[ ] Fix templates

[ ] Documentation

Estimates