Up the limit in development as well

To keep the development env in sync with the other environments
Increase client limit for frontend nginx server

Of course, if we increase the limit on the backend app server, we also
need to increase it in the frontend vhost that passes the request
through to the backend.
Merge pull request #433 from alphagov/increase-request-limit-in-dev-and-nginxfrontend

Increase request limit in dev and nginxfrontend