websites: dustin.hatch.n: Switch to mod_md for cert

The _dustin.hatch.name_ site now obtains its certificate from Let's
Encrypt using the Apache _mod_md_ (managed domain) module.  This
dramatically simplifies the deployment of this certificate, eliminating
the need for _cert-manager_ to obtain it, _cert-exporter_ to add it to
_certs.git_, and Jenkins to push it out to the web server.

roles/websites/dustin.hatch.name/files/dustin.hatch.name.httpd.conf

@@ -1,4 +1,5 @@
 # vim: set ft=apache :
+MDomain dustin.hatch.name
 
 <VirtualHost _default_:80>
 ServerName dustin.hatch.name
@@ -11,8 +12,6 @@ RewriteRule (.*) https://%{SERVER_NAME}$1 [R=301,L]
 ServerName dustin.hatch.name
 
 Include conf.d/ssl.include
-SSLCertificateKeyFile /etc/pki/tls/private/dustin.hatch.name.key
-SSLCertificateFile /etc/pki/tls/certs/dustin.hatch.name.cer
 
 <IfModule mod_headers.c>
     Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"