We use show_diff: false on file.managed states where the file may
contain secrets (from pillar)
The default_server is the nginx server block that is matched if no
other server block is matched. This term is used in listen_addresses
and site-catchall.conf. It redirects people to habhub.org.
Other states don't need to touch this.
The default_host is the server block that handles requests that
do not have a Host header (i.e., HTTP/1.0 clients). This is
used in site-template.conf, and so should be set to true in
one nginx-site.conf per VM.