LuisRecognizer refactor and addition of V3 endpoint (#1479)

* LuisRecognizer refactor and addition of V3 endpoint

* Fixing PR feedback

* Adding missing file header

* Adding tests to V3 scenarios

Author: munozemilio

libraries/botbuilder-ai/src/luisRecognizer.ts

@@ -0,0 +1,27 @@
+/**
+ * @module botbuilder-ai
+ */
+/**
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License.
+ */
+
+import {LuisApplication, LuisRecognizerOptions}  from './luisRecognizer'
+import { RecognizerResult, TurnContext } from 'botbuilder-core';
+
+export abstract class LuisRecognizerInternal {
+ 
+    constructor(application: LuisApplication, options?: LuisRecognizerOptions)
+    {
+        if (!application) {
+            throw new Error('Null Application\n');
+        }
+        this.application = application;
+        this.application.endpoint = this.application.endpoint ? this.application.endpoint : 'https://westus.api.cognitive.microsoft.com';
+    }
+
+    application: LuisApplication;
+
+    abstract recognizeInternalAsync(context: TurnContext): Promise<RecognizerResult>;
+
+}