Change the APIs to instantiate Resource and ResourceId

Now, DiscreteResource/DiscreteResourceId is provided by DiscreteFactory.
Similarly, ContinuousResource/ContinuousResourceId is provided by
ContinuousFactory. These factory instances can be obtained by static
factory method such as Resource.discrete(...) or Resource.continuous(...).

Change-Id: Ic94f7336c0e1f74cf2dddcac899de300362aff3e
diff --git a/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResource.java b/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResource.java
index af34bc5..f5301f7 100644
--- a/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResource.java
+++ b/core/api/src/main/java/org/onosproject/net/newresource/ContinuousResource.java
@@ -98,7 +98,7 @@
 
     @Override
     public Optional<DiscreteResource> parent() {
-        return id.parent().map(DiscreteResource::new);
+        return id.parent().map(x -> Resource.discrete(x).resource());
     }
 
     @Override