Organization details page made admin only
Created by: philmcmahon
Added a custom view for the OrganizationDetail view of django-organizations that uses the AdminRequiredMixin to prevent access of non-admin users to the page. Non-admin users accessing /organizations/(id)/ will get a blank white page with "Sorry, admins only'.
Test for this in organization_test.py.
Kanban ticket: https://aptivate.kanbantool.com/boards/5986-econsensus#tasks-1388749