Refactor CORS configuration and add utility, update package.json for dev start command, and create GraphQL query/mutation files

src/main.ts

@@ -1,15 +1,10 @@
 import { NestFactory } from '@nestjs/core';
 import { AppModule } from './app.module';
+import { cors } from './common/utils/cors.utils';
 
 async function bootstrap() {
   const app = await NestFactory.create(AppModule);
-  app.enableCors({
-    origin: '*',
-    methods: 'GET,HEAD,PUT,PATCH,POST,DELETE',
-    preflightContinue: false,
-    optionsSuccessStatus: 204,
-    credentials: true,
-  });
+  app.enableCors(cors);
   await app.listen(3000);
 }
 bootstrap();