Add User index action and view.

* New scope same_realestate, to get owners that belongs to some agent.
Fix admin/_nav_header Users link
Add edit, update and destroy actions and views.
Refactoring User form

* add form partial
* add new view
* delete admin_new and agent_new views
Refactoring '/admin/dashboard' to admin_dashboard_path

* Undo resource dashboard until we need it
Fix rebase issues.