Make the admin auth providers configurable. Refactor overall config.

The general new approach is that this app will now be passed the global
api umbrella config that the router and gatekeeper also use. This
prevents duplicate config and simplifies where the overall api umbrella
config gets setup.

Also fix some defunct references to the old contact page (since the
contact page will now exist outside of this rails app).
Fix extra empty line making rubocop unhappy.