Deprecate mcast APIs so they can be moved to an app later

Change-Id: I6d9745be4aa9052b03ccc5d1e55d1fd3970f1eee
diff --git a/core/api/src/main/java/org/onosproject/net/mcast/McastStoreDelegate.java b/core/api/src/main/java/org/onosproject/net/mcast/McastStoreDelegate.java
index 638a3f3..1bfd278 100644
--- a/core/api/src/main/java/org/onosproject/net/mcast/McastStoreDelegate.java
+++ b/core/api/src/main/java/org/onosproject/net/mcast/McastStoreDelegate.java
@@ -20,6 +20,10 @@
 
 /**
  * Mcast store delegate abstraction.
+ *
+ * @deprecated in 1.11 ("Loon") release. To be moved into an app.
  */
+
+@Deprecated
 public interface McastStoreDelegate extends StoreDelegate<McastEvent> {
 }