Optimize the self monitoring grafana dashboard. (#6549)

CHANGES.md

@@ -53,6 +53,7 @@ Release Notes.
 * Fix receiver don't need to get itself when healthCheck
 * Remove group concept from AvgHistogramFunction. Heatmap(function result) doesn't support labels.
 * Support metrics grouped by scope labelValue in MAL, no need global same labelValue as before.
+* Optimize the self monitoring grafana dashboard.
 
 #### UI
 * Update selector scroller to show in all pages.

docs/en/setup/backend/backend-telemetry.md

@@ -49,7 +49,8 @@ telemetry:
 ```
 
 ### Grafana Visualization
-Provide the grafana dashboard settings. Check [SkyWalking Telemetry dashboard](grafana.json) config.
+Provide the grafana dashboard settings. 
+Check [SkyWalking OAP Cluster Monitor Dashboard](grafana-cluster.json) config and [SkyWalking OAP Instance Monitor Dashboard](grafana-instance.json) config.
 
 
 ## Self Observability