Manifests for Kubernetes Prometheus

The Prometheus server monitoring Kubernetes should be default cover:
- node exporter
- kubelets
- kube-state-metrics
- apiservers

The version in this commit still has certificate issues with the API
server in minikube. Kubelet scraping likely only works in minikube as it
doesn't seem to use https.

manifests/prometheus/prometheus-k8s.yaml

@@ -0,0 +1,7 @@
+apiVersion: prometheus.coreos.com/v1alpha1
+kind: Prometheus
+metadata:
+  name: prometheus-k8s
+  labels:
+    prometheus: k8s
+spec: {}