Create a nginx_certbot_site resource to remove duplication

It creates a folder, the nginx vhost for certbot and HTTP redirects, and
also runs certbot and recreates the nginx vhost that includes the TLS
cert

site-cookbooks/kosmos-nginx/templates/default/nginx_conf_certbot.erb

@@ -0,0 +1,11 @@
+# Used by Let's Encrypt (certbot in webroot mode)
+server {
+  listen 80;
+  server_name <%= @server_name %>;
+  location /.well-known {
+    root "<%= @root_directory %>";
+  }
+  location / {
+    return 301 https://$host$request_uri;
+  }
+}