title: generating swagger json file without running nest js server
body: <br />
  does anyone know of a way(either official or through a 3rd-party tool) to generate swagger json files without needing the nest js server to run?
  <p>I have a nest js application with controller routes and DTO's annotated with @nest/swagger decorators for documentation. I know I can get the swagger json files by starting the server and visiting /api-json but I need the ability to generate this file without having to start the server first.</p>