add valid cert to internal communication

roles/webgateway/files/prometheus-nginx-exporter

@@ -0,0 +1,14 @@
+ARGS="-nginx.scrape-uri http://127.0.0.1:8888/stub_status"
+
+# Prometheus-nginx-exporter supports the following options:
+#  -nginx.plus
+#        Start the exporter for NGINX Plus. By default, the exporter is started
+#        for NGINX.
+#  -nginx.scrape-uri string
+#        A URI for scraping NGINX or NGINX Plus metrics.
+#        For NGINX, the stub_status page must be available through the URI.
+#        For NGINX Plus -- the API. (default "http://127.0.0.1:8080/stub_status")
+#  -web.listen-address string
+#        An address to listen on for web interface and telemetry. (default ":9113")
+#  -web.telemetry-path string
+#        A path under which to expose metrics. (default "/metrics"