Engine: Fixes #3372: Inital work to enable the dashboard.

This initial work fixes the basics of the Dashboard. The System and
Notices widgets are enabled and working. The Content Views, Promotions,
and Sync Overview widgets rely upon further work in those areas to come
to life.
Merge pull request #3222 from ehelms/engine-dashboard

Engine: Fixes #3372: Inital work to enable the dashboard.