chore: migrate backend to monorepo apps and biome

apps/bookings/src/main.ts

@@ -0,0 +1,8 @@
+import { NestFactory } from '@nestjs/core';
+import { BookingsModule } from './bookings.module';
+
+async function bootstrap() {
+  const app = await NestFactory.create(BookingsModule);
+  await app.listen(process.env.BOOKING_PORT ?? 3004);
+}
+bootstrap();