feat(classes): implement initiation, start work on dbHelper

lib/main.dart

@@ -6,7 +6,7 @@ import 'transport_helper.dart';
 void main() async {
   await dotenv.load();
   const String dbName = "oeffimasterTransportDb";
-  initDB(dbName);
+  DbHelper.initDb(dbName);
   runApp(const MyApp());
 }
 
@@ -145,4 +145,4 @@ class _MyHomePageState extends State<MyHomePage> {
       ),
     );
   }
-}
+}