more test for MSK/Kafka

[lmatz]

quote from @twocode:

I feel like we only tested the easy path with MSK (at least from our documentation). We didn’t test our the complex part, for example the public access has the most complex config of network, security groups, server setting and ACL rules. It’s not well documented.

The current MSK documentation: https://docs.risingwave.com/docs/current/connector-amazon-msk/

[github-actions]

This issue has been open for 60 days with no activity. Could you please update the status? Feel free to continue discussion or close as not planned.

[neverchanje]

The only feature that I am aware but unsupported now is "ssh tunnel", which allow clients outside AWS to connect to MSK through a jumpserver.
Leaving it aside, I am unaware of other lacking features for Kafka source. A difference between MSK and self-hosted Kafka is AWS IAM auth, which has recently been supported.
In general, I don't agree with the idea that "we only tested the easy path with MSK".