feat: Convert routes folder to the js files

packages/backend/src/routes/index.js

@@ -0,0 +1,12 @@
+import { Router } from 'express';
+import graphQLInstance from '../helpers/graphql-instance';
+import webhooksRouter from './webhooks';
+import paddleRouter from './paddle.ee';
+
+const router = Router();
+
+router.use('/graphql', graphQLInstance);
+router.use('/webhooks', webhooksRouter);
+router.use('/paddle', paddleRouter);
+
+export default router;