Adding skeletal structure for the ONLP gNMI GUI demo.

Change-Id: I6796ebf200e20a51bdc098fcc3696b78d7c1132e
diff --git a/apps/onlp-demo/src/main/resources/app/view/odTopov/odTopov.js b/apps/onlp-demo/src/main/resources/app/view/odTopov/odTopov.js
new file mode 100644
index 0000000..d78c009
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+++ b/apps/onlp-demo/src/main/resources/app/view/odTopov/odTopov.js
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2015-present Open Networking Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ Module containing the "business logic" for the layout topology overlay.
+ */
+
+(function () {
+    'use strict';
+
+    // injected refs
+    var $log, flash, wss;
+
+    function doFoo(type, description) {
+        flash.flash(description);
+        wss.sendEvent('doFoo', {
+            type: type
+        });
+    }
+
+    function clear() {
+        // Nothing to do?
+    }
+
+    angular.module('ovOdTopov', [])
+        .factory('OnlpDemoTopovService',
+        ['$log', 'FlashService', 'WebSocketService',
+
+        function (_$log_, _flash_, _wss_) {
+            $log = _$log_;
+            flash = _flash_;
+            wss = _wss_;
+
+            return {
+                doFoo: doFoo,
+                clear: clear
+            };
+        }]);
+}());