Add roadmap, fix manifests, improve hack scripts

README.md

hack/cluster-monitoring/deploy

hack/cluster-monitoring/teardown

hack/example-service-monitoring/teardown

manifests/controllers/alertmanager-controller.yaml

manifests/controllers/prometheus-controller.yaml

manifests/examples/example-app/prometheus-frontend-svc.yaml

manifests/grafana/grafana-depl.yaml

manifests/grafana/grafana-svc.yaml

manifests/prometheus/prometheus-k8s-cm.yaml

manifests/prometheus/prometheus-k8s-svc.yaml