[openapi-to-tsp][Feature request] Generate response headers defined in swagger

[catalinaperalta]

The converter currently seems to ignore response headers defined in swagger when converting to TypeSpec. Some specifications that widely use response headers, like App Configuration, would benefit from outputting response headers to reduce the amount of work necessary post conversion.

Example specification: https://github.com/Azure/azure-rest-api-specs/blob/main/specification/appconfiguration/data-plane/Microsoft.AppConfiguration/stable/2023-11-01/appconfiguration.json

Example readme: https://github.com/Azure/azure-rest-api-specs/blob/main/specification/appconfiguration/data-plane/readme.md

cc @joheredi