sync roles with changes from OWS

roles/nginx_exporter/templates/nginx_exporter.service.j2

@@ -0,0 +1,17 @@
+## Managed by Ansible ##
+
+[Unit]
+Description=Prometheus Nginx Exporter
+Requires=nginx.service
+After=nginx.service
+
+[Service]
+Type=simple
+User={{ nginx_exporter_system_user }}
+Group={{ nginx_exporter_system_group }}
+ExecStart={{ nginx_exporter_install_dir }}/nginx-prometheus-exporter -nginx.scrape-uri=unix:{{ nginx_stub_status_socket }}:/stub_status
+Restart=always
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target