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

03-configmaps.yaml

@@ -19,6 +19,7 @@ data:
           prefix: coordinator
         prometheus:
           handlerPath: /metrics
+          listenAddress: 0.0.0.0:7203
         sanitization: prometheus
         samplingRate: 1.0
         extended: none
@@ -31,12 +32,8 @@ data:
       logging:
         level: info
 
-      metrics:
-        prometheus:
-          handlerPath: /metrics
-        sanitization: prometheus
-        samplingRate: 1.0
-        extended: detailed
+      # Metrics handled by coordinator section above (port 7203)
+      # db-specific metrics disabled to avoid port conflict
 
       listenAddress: 0.0.0.0:9000
       clusterListenAddress: 0.0.0.0:9001
@@ -199,6 +196,7 @@ data:
         prefix: coordinator
       prometheus:
         handlerPath: /metrics
+        listenAddress: 0.0.0.0:7203
       sanitization: prometheus
       samplingRate: 1.0
 
@@ -251,15 +249,10 @@ data:
               - resolution: 1m
                 retention: 8760h
 
-    # Ingest — Prometheus remote write
-    ingest:
-      ingester:
-        workerPoolSize: 10000
-        opPool:
-          size: 10000
-      m3msg:
-        server:
-          listenAddress: 0.0.0.0:7507
+    # Ingest — Prometheus remote write (uses defaults)
+    # ingest:
+    #   ingester:
+    #     workerPoolSize: 10000
 
     # Carbon ingestion disabled (uncomment if needed)
     # carbon: