Fix m3dbnode port conflict, update README, fix test script

- Remove duplicate db.metrics section (port 7203 conflict)
- Fix coordinator health endpoint (/health not /api/v1/services/m3db/health)
- Update README: remove NodePort references, always use LoadBalancer
- Add bootstrap instructions (workaround for init job chicken-and-egg)
- Fix test-metrics.sh: correct health endpoint and JSON parsing

kustomization.yaml

@@ -1,4 +1,4 @@
-apiVersion: kustomize.k8s.io/v1beta1
+apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 
 resources: