[ADF-1549] Added files for Core library (#2345)

* [ADF-1549] Added files for Core library

* [ADF-1549] Updated md files following checks

docs/notification.service.md

@@ -0,0 +1,50 @@
+# Notification Service
+
+Shows a notification message with optional feedback.
+
+<!-- markdown-toc start - Don't edit this section.  npm run toc to generate it-->
+
+<!-- toc -->
+
+- [Details](#details)
+
+<!-- tocstop -->
+
+<!-- markdown-toc end -->
+
+## Details
+
+The Notification Service is implemented on top of the Angular 2 Material Design snackbar.
+Use this service to show a notification message, and optionally get feedback from it.
+
+```ts
+import { NotificationService } from 'ng2-alfresco-core';
+
+export class MyComponent implements OnInit {
+
+    constructor(private notificationService: NotificationService) {
+    }
+
+    ngOnInit() {
+          this.notificationService.openSnackMessage('test', 200000).afterDismissed().subscribe(() => {
+                    console.log('The snack-bar was dismissed');
+                });
+    }
+}
+```
+
+```ts
+import { NotificationService } from 'ng2-alfresco-core';
+
+export class MyComponent implements OnInit {
+
+    constructor(private notificationService: NotificationService) {
+    }
+
+    ngOnInit() {
+         this.notificationService.openSnackMessageAction('Do you want to report this issue?', 'send', 200000).afterDismissed().subscribe(() => {
+                console.log('The snack-bar was dismissed');
+            });
+    }
+}
+```