Refactoring of the entitlement trait to remove the "namespaces" method.

This belongs in an IAM provider interface - so create a new Identities type to host this method.
This refactoring is the first toward allowing multiple namespaces for a subject, each having its own key.
So currently still allow a subject to work acorss any of their namespaces but this will be removed in a future
iteration and hence will break the IAM entanglement with entitlement.

Also fixed some gaps in the Config type which ignored optional properties except when reading from consul.

Fixes issue #1470.

tests/src/whisk/core/controller/test/ControllerTestCommon.scala

@@ -39,6 +39,7 @@ import whisk.core.database.test.DbUtils
 import whisk.core.entitlement.{ Collection, EntitlementService, LocalEntitlementService }
 import whisk.core.entity._
 import whisk.core.loadBalancer.LoadBalancer
+import whisk.core.iam.Identities
 
 
 protected trait ControllerTestCommon
@@ -63,7 +64,8 @@ protected trait ControllerTestCommon
     assert(whiskConfig.isValid)
 
     override val loadBalancer = new DegenerateLoadBalancerService(whiskConfig, InfoLevel)
-    override val entitlementService: EntitlementService = new LocalEntitlementService(whiskConfig, loadBalancer)
+    override val iam = new Identities(whiskConfig, forceLocal = true)
+    override val entitlementService: EntitlementService = new LocalEntitlementService(whiskConfig, loadBalancer, iam)
 
     override val activationId = new ActivationId.ActivationIdGenerator() {
         // need a static activation id to test activations api