Extend OpenApiSpecGeneratorPlugin with the option to ignore response types

[waldekmastykarz]

Let's extend the OpenApiSpecGeneratorPlugin with the option to ignore the response types. When building specs for the sole purpose of integrating with LLMs, response types are ignored in most cases. Removing them from the spec, decreases its size and makes it easier for the LLM to process. We still should generate types for request payloads.

Extend the plugin with a new bool configuration property named ignoreResponseTypes. By default it's false. When set to true, it leads to the plugin skipping parsing response data. Instead, it marks the response type as string.