do not minify dev content server

## Depends on https://github.com/mozilla/fxa-content-server/pull/1763
@zaach I'm worried that we will not have a good deployment with minified resources, r? 
@dannycoates would passing an option such as `--no-minify` work with Ansible, r?



Fixes https://github.com/mozilla/fxa-content-server/issues/1759