[Aether-1482] - Add the new helm chart to install the telegraf external daemon of ONOS controller

- Use the servicemonitor to work with Prometheus instead of Rancher's annotation

Change-Id: Icabfb43b1dbf5f86bfdbd4117cf550770d3418a7
diff --git a/apps/tost-telegraf/templates/servicemonitor.yaml b/apps/tost-telegraf/templates/servicemonitor.yaml
new file mode 100644
index 0000000..5959341
--- /dev/null
+++ b/apps/tost-telegraf/templates/servicemonitor.yaml
@@ -0,0 +1,18 @@
+{{/*
+# Copyright 2021-present Open Networking Foundation
+
+# SPDX-License-Identifier: LicenseRef-ONF-Member-Only-1.0
+*/}}
+
+apiVersion: monitoring.coreos.com/v1
+kind: ServiceMonitor
+metadata:
+  name: tost-telegraf
+spec:
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: telegraf
+  endpoints:
+  - port: prometheus-client
+    path: /metrics
+    scheme: HTTP