Implement replicaLoadBalancer boolean flag. (#38)

The flag adds a replica service with the name cluster_name-repl and
a DNS name that defaults to {cluster}-repl.{team}.{hostedzone}.

The implementation converted Service field of the cluster into a map
with one or two elements and deals with the cases when the new flag
is changed on a running cluster
(the update and the sync should create or delete the replica service).
In order to pick up master and replica service and master endpoint
when listing cluster resources.

* Update the spec when updating the cluster.

pkg/util/config/util.go

@@ -9,7 +9,7 @@ import (
 	"time"
 )
 
-type Decoder interface {
+type decoder interface {
 	Decode(value string) error
 }
 
@@ -21,15 +21,15 @@ type fieldInfo struct {
 
 type stringTemplate string
 
-func decoderFrom(field reflect.Value) (d Decoder) {
+func decoderFrom(field reflect.Value) (d decoder) {
 	// it may be impossible for a struct field to fail this check
 	if !field.CanInterface() {
 		return
 	}
 
-	d, ok := field.Interface().(Decoder)
+	d, ok := field.Interface().(decoder)
 	if !ok && field.CanAddr() {
-		d, _ = field.Addr().Interface().(Decoder)
+		d, _ = field.Addr().Interface().(decoder)
 	}
 
 	return d