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

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

Start by reading the openapi-to-tsp converter and the linked App Configuration specification and readme, focusing on response headers defined in Swagger. Done means the converter represents those response headers in the generated TypeSpec output and the example specification no longer requires manual post-conversion work.

Written by the indexing model from the issue text.