API naming for LG (#1883)

* rename lg

* rename templates property to items

* rename

* rename

* Updated Templates to look like a collection

* Fixed unit tests

Co-authored-by: Steven Ickman <stevenic@microsoft.com>

Author: Danieladu

libraries/botbuilder-core/src/activityFactory.ts

@@ -7,6 +7,7 @@
  */
 
 export * from 'botframework-schema';
+export * from './activityFactory';
 export * from './appCredentials';
 export * from './activityHandler';
 export * from './activityHandlerBase';

libraries/botbuilder-core/src/index.ts

@@ -94,19 +94,19 @@ For NodeJS, add botbuilder-lg
 Load the template manager with your .lg file
 
 ```typescript
-    let lgFile = new LGParser.parseFile(filePath, importResolver?, expressionParser?);
+    let templates = new Templates.parseFile(filePath, importResolver?, expressionParser?);
 ```
 
-When you need template expansion, call the LGFile and pass in the relevant template name
+When you need template expansion, call the templates and pass in the relevant template name
 
 ```typescript
-    await turnContext.sendActivity(lgFile.evaluateTemplate("<TemplateName>", entitiesCollection));
+    await turnContext.sendActivity(templates.evaluate("<TemplateName>", entitiesCollection));
 ```
 
 If your template needs specific entity values to be passed for resolution/ expansion, you can pass them in on the call to `evaluateTemplate`
 
 ```typescript
-    await turnContext.sendActivity(lgFile.evaluateTemplate("WordGameReply", { GameName = "MarcoPolo" } ));
+    await turnContext.sendActivity(templates.evaluate("WordGameReply", { GameName = "MarcoPolo" } ));
 ```
 
 [1]:https://github.com/Microsoft/BotBuilder/blob/master/specs/botframework-activity/botframework-activity.md