Extend host structures to store multiple locations

Also update host location format in CLI and REST API

Change-Id: I0fbd655f642627dd3eb8a2925f83a3ee016fe4aa
diff --git a/core/common/src/test/resources/org/onosproject/codec/impl/VirtualHost.json b/core/common/src/test/resources/org/onosproject/codec/impl/VirtualHost.json
index ab5a81b..818ce0b 100644
--- a/core/common/src/test/resources/org/onosproject/codec/impl/VirtualHost.json
+++ b/core/common/src/test/resources/org/onosproject/codec/impl/VirtualHost.json
@@ -6,8 +6,10 @@
     "1.1.1.1",
     "2.2.2.2"
   ],
-  "location": {
-    "elementId": "of:d1",
-    "port": "1"
-  }
+  "locations": [
+    {
+      "elementId": "of:d1",
+      "port": "1"
+    }
+  ]
 }