Rework cluster metrics dashboard to support the modern clusters

metrics/scripts/start.sh

@@ -34,7 +34,7 @@ source lib/config.sh
 if [[ ! -f lib/grafana-provisioning ]]; then
   cp -va grafana-provisioning lib
   ./adjust-dashboard-for-channel.py \
-    lib/grafana-provisioning/dashboards/testnet-monitor.json local
+    lib/grafana-provisioning/dashboards/cluster-monitor.json local
 
   mkdir -p lib/grafana-provisioning/datasources
   cat > lib/grafana-provisioning/datasources/datasource.yml <<EOF