[#626] Tweaks dashboard to have 3 new subpages

A my datasets, my orgs and my groups pages. Each one showing ownership of the
relevant items within it.
[#506] Tidys up views to have better breadcrumbs for editin user
[#626] Use helper functions to get orgs/groups for dashboard plus cleanups
Merge master
[#626] Fix for dashboard templates to go full width
[#626] Tweak groups_available docstring
[#626] Tweak docstring for am_member param
[#626] Tweak docstring for am_member param
Merged master
[#626] Small textual tweak
[#626] Add display_name to group/org list for user action
Merge branch '626-dashboard-update'