Enabled --prod mode for GUI2 - refactored modules

Change-Id: I224fe9564cb225b9ebaed0a43281de54ec6eb274
diff --git a/web/gui2/src/main/webapp/app/log.service.ts b/web/gui2/src/main/webapp/app/log.service.ts
index 3dc54a1..2835371 100644
--- a/web/gui2/src/main/webapp/app/log.service.ts
+++ b/web/gui2/src/main/webapp/app/log.service.ts
@@ -26,7 +26,9 @@
  * ONOS GUI -- LogService
  * Inspired by https://robferguson.org/blog/2017/09/09/a-simple-logging-service-for-angular-4/
  */
-@Injectable()
+@Injectable({
+  providedIn: 'root',
+})
 export class LogService extends Logger {
   debug: any;
   info: any;