FE: Move GA to head
Remove unused `state-templates` code
FE: Use `strong` instead of quotes

As the text highlighted is what user is expected to type it helps
to reduce vagueness by removing the quotes in case user thinks
it's part of the case.
FE: Add static template 500 error template
Update nginx config to include 500 error pages location
Merge pull request #313 from ministryofjustice/feature/error-pages

Feature/error pages
BE: Remove debug 500 error view
Nginx 500 debug URL
Merge pull request #314 from ministryofjustice/feature/error-pages

Feature/error pages
Remove debug 500 location from Nginx config
start page translations
400 page trans
500 trans
page title trans
404 trans
elements trans
confirmation trans
eligible page
no callback trans
face-to-face trans