Allow additional vhosts

Since Opencast 16+ requires OpenSearch on the admin and presentation nodes, we should provide an option to create a virtual host for this purpose. With this patch all additional vhost configurations from /etc/nginx/sites-enabled/ will be loaded.

README.md

@@ -36,11 +36,13 @@ If you want to use Let's Encrypt to generate certificates, you can also include
 [`elan.opencast_certbot`](https://galaxy.ansible.com/elan/opencast_certbot)
 which will automatically generate TLS certificates for you.
 
-
 You can also add some custom configuration in the file `/etc/nginx/conf.d/extra.conf`.
 The file is included after Opencast's main `location` block.
 The role will not modify this file if it exists.
 
+Additionally you can define other virtual hosts in `/etc/nginx/sites-enabled/` directory.
+They will be loaded as well.
+
 
 Example Playbook
 ----------------
@@ -72,7 +74,7 @@ The role will _not_ replace an existing certificate so you can safely use a `fil
         owner: root
         group: root
         mode: '0400'
-      notify: reload nginx
+      notify: Reload nginx
       loop:
         - key
         - crt

templates/nginx.conf

@@ -153,4 +153,7 @@ http {
     # Include additional custom configuration
     include /etc/nginx/conf.d/extra.conf;
   }
+
+  # Include dynamic virtual host configurations
+  include /etc/nginx/sites-enabled/*;
 }