* [Modified] Makefile to run kustomize.jsonnet
* [Modified] Moved kustomization from example.jsonnet to
examples/kustomize.jsonnet
* [Modified] kustomization file to land at root of kube-prometheus so
current users can continue to use `kubectl apply -f manifests`

Closes #2391

Adds support to allow kustomize users to point to a [remote
base](https://github.com/kubernetes-sigs/kustomize/blob/master/examples/remoteBuild.md) of the prometheus-operator and kube-prometheus. Now that kustomize is a part of kubectl, this is provides a very simple way of installing prometheus-operator and kube-prometheus with no additional tools besides kubectl.

* [Added] kustomization.yaml: hardcoded kustomization base for prometheus-operator
bundle.yaml
* [Added] kustomization generation from kube-prometheus example jsonnet

contrib/kube-prometheus: Add section on Prometheus Adapter requirements to README.md