Update nginx configuration to make possible to include more configuration files by default

roles/webserver/templates/nginx/nginx.conf.j2

@@ -182,3 +182,10 @@ http {
     # Virtual hosts inclusion
     include /etc/nginx/sites-enabled/*;
 }
+
+#
+# Include more global diretives (mail, rtmp, etc.)
+#
+
+include /etc/nginx/conf.d/*.inc;
+