Use grafanalib to generate Grafana dashboards

Makefile

@@ -1,4 +1,11 @@
-BUILDER := docker run --rm -it --workdir /data -v ${PWD}:/data debian:8 ./hack/scripts/generate-manifests.sh
-generate:
+.PHONY: image
+	
+IMAGE := coreos/generate-prometheus-operator-manifests
+
+image: Dockerfile
+	docker build -t $(IMAGE) .
+
+BUILDER := docker run --rm -it --workdir /data -v ${PWD}:/data $(IMAGE) ./hack/scripts/generate-manifests.sh
+generate: image
 	@echo ">> Compiling assets and generating Kubernetes manifests"
 	$(BUILDER)