Allow caching the QA in Fastly and Varnish
Allow caching the QA in Fastly and Varnish

Similar to what we've done to normal finders
(https://github.com/alphagov/finder-frontend/pull/722)
we want to set approriate cache headers on the QA tool allowing it
to be cached by Fastly and Varnish.

alphagov/finder-frontend,alphagov/finder-frontend,alphagov/finder-frontend,alphagov/finder-frontend