Pass Host/X-Forwarded-For everywhere

It hasn't mattered much to have these so far, but
it's probably a good idea to have them.

roles/matrix-nginx-proxy/templates/nginx-conf.d/matrix-riot-web.conf.j2

@@ -50,6 +50,7 @@ server {
 			proxy_pass http://localhost:8765;
 		{% endif %}
 
-        proxy_set_header X-Forwarded-For $remote_addr;
+		proxy_set_header Host $host;
+		proxy_set_header X-Forwarded-For $remote_addr;
     }
 }