Make s095's host_vars file readable
Major clean up of nginx role

The nginx main task is now split into two. One somewhat simplified task
for managing basic nginx configuration, and one for installing SSL
certificates as and where they are needed.

In addition, this commit:

- renames ssl_sites_enabled to nginx_ssl_certs
- adds appropriate "notify" directives so that nginx is actually
  reloaded when config changes
- uses the ansible "service" module to provide the "reload nginx"
  handler, which will call /etc/init.d/nginx reload, which will in turn
  do a configtest itself before reloading nginx
Move SSL cipher configuration into its own file
openspending: update config with new ssl location