Add NTT dashboard

Change-Id: I235994346bd506bbe1473ea01e7b16fb0f64aa31
diff --git a/monitoring/grafana-aether/dashboards/ntt-system.json.license b/monitoring/grafana-aether/dashboards/ntt-system.json.license
new file mode 100644
index 0000000..c522327
--- /dev/null
+++ b/monitoring/grafana-aether/dashboards/ntt-system.json.license
@@ -0,0 +1,2 @@
+Copyright 2020-present Open Networking Foundation
+SPDX-License-Identifier: LicenseRef-ONF-Member-Only-1.0