fix nginx proxy configuration conflicts (#3489)

* Allow configuration of nginx proxy config path

* Fix the internal nginx configuration location

Signed-off-by: Johann Queuniet <contact@lordran.net>

roles/kubernetes/node/templates/manifests/nginx-proxy.manifest.j2

@@ -33,4 +33,4 @@ spec:
   volumes:
   - name: etc-nginx
     hostPath:
-      path: /etc/nginx
+      path: {{ nginx_config_dir }}