Draconian control of nginx config files

Changed the nginx configuration & sites-enabled mechanisms to look for unmanaged files and delete them.

The default files I found to be installed by nginx were either useless (commented out) or harmful (/etc/nginx/conf.d/default.conf actually defined a virtual server on port 80). This solution removes those defaults in favor of my ansible configuration.

Additionally, this patch simplifies the process of deleting once-managed config files – previously, I had to delete the yml stanza and file separately, but this gracefully removes the .conf file when I delete the stanza.