Allow configuration of bootstrap API server

This avoids possible issues when the configuration of the bootstrapping
apiserver differs from the chart's configuration.  Issues were
specifically seen when overriding the node port range, but this opens up
additional configuration also.

Change-Id: I2a3fc5847e850c8055c099bac50782debbbabbf4

examples/basic/armada-resources.yaml

@@ -578,10 +578,11 @@ data:
   values:
     conf:
       anchor:
-        kubernetes_url: https://kubernetes.default:443
+        kubernetes_url: https://10.96.0.1:443
         services:
-          default:
-            kubernetes:
+          default: null
+          kube-system:
+            kubernetes-apiserver:
               server_opts: "check port 6443"
               conf_parts:
                 frontend:
@@ -591,7 +592,6 @@ data:
                   - mode tcp
                   - option tcp-check
                   - option redispatch
-          kube-system:
             kubernetes-etcd:
               server_opts: "check port 2379"
               conf_parts: