Make replication factor check opt-in

[snicoll]

The current Kafka health indicator attempts to retrieve a replication factor regardless of the fact that the application uses transaction or not.

We should make that check opt-in.

See #11515 (comment)

and this commit we can't use as looking for properties is not really legit there and there might be many other ways for the user to configure that stuff anyway.

[snicoll]

After discussing with @wilkinsona we decided to make that check opt-in due to the number of issues that's raising. I am working on a proposal.

/cc @garyrussell

[snicoll]

We've been looking at this issue most of today and came to the conclusion it isn't mature enough for us to provide a health indicator out of the box. We'll revert it and reconsider this feature for a latter release.