chore: imported example from the private kb

examples/kubernetes/prometheus on k8s using helm.md

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+# Prometheus on Kubernetes using Helm
+
+Installation:
+
+```sh
+helm upgrade --install --namespace monitoring --create-namespace prometheus prometheus-community/prometheus
+```
+
+The server can be accessed via port 80 on `prometheus-server.monitoring.svc.cluster.local` from within the cluster.
+
+Get the server URL:
+
+```sh
+export POD_NAME=$(kubectl get pods --namespace monitoring -l "app=prometheus,component=server" -o jsonpath="{.items[0].metadata.name}")
+kubectl --namespace monitoring port-forward $POD_NAME 9090
+```
+
+Alertmanager can be accessed via port 80 on `prometheus-alertmanager.monitoring.svc.cluster.local` from within the cluster
+
+Get Alertmanager's URL:
+
+```sh
+export POD_NAME=$(kubectl get pods --namespace monitoring -l "app=prometheus,component=alertmanager" -o jsonpath="{.items[0].metadata.name}")
+kubectl --namespace monitoring port-forward $POD_NAME 9093
+```
+
+PushGateway can be accessed via port 9091 on `prometheus-pushgateway.monitoring.svc.cluster.local` from within the cluster
+
+Get PushGateway's URL:
+
+```sh
+export POD_NAME=$(kubectl get pods --namespace monitoring -l "app=prometheus,component=pushgateway" -o jsonpath="{.items[0].metadata.name}")
+```
+
+## Further readings
+
+- [Install Prometheus and Grafana with helm 3 on a local machine VM]
+- [Set up prometheus and ingress on kubernetes]
+
+## Sources
+
+All the references in the [further readings] section, plus the following:
+
+- [Helm chart]
+
+<!-- project's references -->
+[helm chart]: https://github.com/prometheus-community/helm-charts/tree/main/charts/prometheus
+
+<!-- internal references -->
+[further readings]: #further-readings
+
+<!-- external references -->
+[install prometheus and grafana with helm 3 on a local machine vm]: https://dev.to/ko_kamlesh/install-prometheus-grafana-with-helm-3-on-local-machine-vm-1kgj
+[set up prometheus and ingress on kubernetes]: https://blog.gojekengineering.com/diy-how-to-set-up-prometheus-and-ingress-on-kubernetes-d395248e2ba