Set up retreatregistrations form & retreat controller

Retreat singular route routes to current youth retreat 'show' form. This form should include marketing materials and basically be a static site that posts to the retreatregistrations controller.
Lots of stuffz
Fixed incorrect retreat registration pluralization
Retreat registration autofilled forms are working!
Removed scaffold css & stray controller in root.
Retreat layout

Added retreat layout for retreat pages and moved top page border to application layout head. The last part may need refactoring.
Added one page scroll.
Stubbed retreat assets from main application.

Stubbed retreat assets and added them into retreat layout via link_tags.
Copy and styling.

Basic stucture, styling, and user auth for page.