feat(kafka): enabling tls connection without client authentication

[brunodomenici]

Kafka TLS

As we can see in #1277 , we can't enable TLS without setting insecureSkipVerify to true or setting client authentication.

I propose a TLS.Enable with default to false (to keep compatibility with existing configurations). With that, we can set only this to true to activate TLS without needing to set other configuration in this object.

Checklist:

• My organization is added to USERS.md.

[whynowy]

Thanks @brunodomenici .

What is the difference between this new property and insecureSkipVerify?

[brunodomenici]

Hello @whynowy
You're welcome.
If we set insecureSkipVerify = true we are not validating broker's certificate. This is a security issue for using this in my company.

[shearn89]

To add a use case here - we deploy AWS MSK, which defaults to security.protocol=SSL for comms even when the cluster requires no auth. We have to currently set insecureSkipVerify = true to connect at all, even though we're not using mTLS. It would be great to be able to use TLS to the broker (but not mTLS), which (if I understand correctly) this PR allows us to do.