Add new grafana dashboards for general kubernetes metrics for trial (#2834)

Adding the new dashboards for a trial period for evaluation. Main focus on: trivy-operator and prometheus dashboards.

Author: chi-quita-a

helmfile.d/charts/grafana-dashboards/dashboards/README.md

@@ -7,3 +7,5 @@ The Rook/Ceph dashboards were found through [this page](https://rook.io/docs/roo
 - Ceph pools: https://grafana.com/dashboards/5342
 
 The Ingress nginx dashboard was likely found through [this page](https://grafana.com/grafana/dashboards/16677-ingress-nginx-overview/). It has at least been altered to work with `honorLabels` in the servicemonitor, i.e. when the `namespace` label points to the ingress namespace instead of the controller namespace.
+
+The Grafana dashboards for general Kubernetes metrics were found on [this page](https://github.com/dotdc/grafana-dashboards-kubernetes).