Migrate to scalar

[CodeName-Anti]

This pull request includes several changes to update the API documentation and improve the server configuration. The most important changes include replacing swagger-ui-express with @scalar/express-api-reference, updating the OpenAPI specification file name, and modifying the NGINX configuration to handle the new OpenAPI endpoint.

API Documentation Updates:

• backend/package.json: Removed swagger-ui-express and added @scalar/express-api-reference to dependencies.
• backend/src/server.ts: Replaced the Swagger UI setup with the apiReference middleware from @scalar/express-api-reference, and updated the endpoint for serving the OpenAPI specification file. [1] [2]
• backend/tsoa.json: Changed the OpenAPI specification file name to openapi.

Server Configuration:

• nginx/nginx.conf: Updated the NGINX configuration to proxy requests for openapi.json to the backend.

[schmolldechse]

Thanks for your hard work!

[schmolldechse]

Would be good if you lint, then I can merge your changes.

[schmolldechse]

Thanks! Looks good now