[helm] Enable the user to set volumes and initContainers for tablet and coordinator

[affo]

Search before asking

• I searched in the issues and found nothing similar.

Motivation

Enable to set volumes, volumeMounts, and initContainers for both tablets and coordinator to allow, for example:

• dynamic plugin installation
• certificate handling (future for TLS)
• configuration injection

See https://github.com/bitnami/charts/blob/main/bitnami/kafka/values.yaml#L418.

Solution

No response

Anything else?

No response

Willingness to contribute

• I'm willing to submit a PR!