DRY-ing up the group browsing feature
A leaf_node is a group without children
Selectively display dependencies on group pages

- Display teams/orgs 'within this group' when they exist

- Display 'people in this group' for leaf nodes, otherwise
provide a link to 'view all people in this group'
Remove inline add team / person links from group

- In anticipation of updated design, we won't be 
linking to these functions from within the page
Edit this 'organisation' becomes edit this 'page'