HTTP-Kafka Proxy: Forward all headers withourt "reply-to"-Topic

[Andy5929]

Is your feature request related to a problem? Please describe.
We are currently using the http-kafka proxy and some endpoints don't need a "reply-to"-Topic. We noticed that the http headers are not forwarded to kafka when the "reply-to"-Topic is not configured.

Describe the solution you'd like
A variable that can be set in the http-kafka-proxy to pass all headers without a reply-to. For example:

- when:
    - path: /test
  exit: kafka_cache_client
  with:
    capability: produce
    topic: testopic
    key: "${idempotencyKey}"
	headers: true

Describe alternatives you've considered
If topic = response-topic sends the header, but correlation-id is unneccessary.
This could also be a possible configuration.