ONOS-3655 - Adding username and password support into the device key subsystem.

Change-Id: I196984479126ae3776093a0bded4b3c820a3eab8
diff --git a/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java b/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java
index 84a439d..0c7bb86 100644
--- a/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java
+++ b/core/api/src/main/java/org/onosproject/net/AnnotationKeys.java
@@ -135,6 +135,16 @@
     public static final String MANAGEMENT_ADDRESS = "managementAddress";
 
     /**
+     * Annotation key for the username.
+     */
+    public static final String USERNAME = "username";
+
+    /**
+     * Annotation key for the password.
+     */
+    public static final String PASSWORD = "password";
+
+    /**
      * Returns the value annotated object for the specified annotation key.
      * The annotated value is expected to be String that can be parsed as double.
      * If parsing fails, the returned value will be 1.0.