[bitnami/kafka] Custom SANs for auto-generated TLS certificates

[xdom]

Description of the change

Allows bitnami/kafka chart users to provide custom additional subject alternative names (SANs) for auto-generated TLS certificates using a tls.customAltNames value.

When external access is enabled (externalAccess.enabled) and service domains are filled (externalAccess.broker.service.domain, externalAccess.controller.service.domain), they are included in SANs, too.

Benefits

Auto-generated TLS certificates will work with domains configured for external access, and any other custom alternative names. Therefore, clients won't be forced to manually generate certificates for their PoC clusters, and won't have to disable hostname verification in clients when connecting via an external domain.

Possible drawbacks

Existing behavior changes, i.e. external access domain names were not previously added into the certificate SANs. This might be unwanted for some users. However, existing clusters will not be affected when using helm upgrade because the chart does not overwrite a TLS secret once it exists.

Applicable issues

N/A

Additional information

N/A

Checklist

• Chart version bumped in Chart.yaml according to semver. This is not necessary when the changes only affect README.md files.
• Variables are documented in the values.yaml and added to the README.md using readme-generator-for-helm
• Title of the pull request follows this pattern [bitnami/<name_of_the_chart>] Descriptive title
• All commits signed off and in agreement of Developer Certificate of Origin (DCO)

[juan131]

Thanks so much for this enhancement! LGTM