[Feat.] Enable grafana to show metrics (#4718)

Co-authored-by: zhaochenyang20 <zhaochen20@outlook.com>

examples/monitoring/grafana/datasources/datasource.yaml

@@ -0,0 +1,8 @@
+apiVersion: 1
+datasources:
+  - name: Prometheus
+    type: prometheus
+    access: proxy
+    url: http://localhost:9090
+    isDefault: true
+    editable: false