Adds stubbed dashboard boxes. #29

Add a dashboard class and stub out what will appear on the dashboard
Adds stubbed out sidebar carousel. #31

Carousel can be configured to show on the sidebar when there is no content for the sidebar

Refactors the sidebar into its own partial

Fixes favicon on the admin layout
Session authorization redirects to previous URL on success. #32

If a user hits an action/page that requires them to be logged in, they will now be redirected back to that page when they successfully login