[TASK] Create extra values file for legacy bitnami repo name

[aabouzaid]

Related to

• Epic: https://github.com/camunda/team-distribution/issues/411
• Task: [TASK] Update Bitnami Docker repo #3884

Overview

We will provide the customers with an extra values file to use, which contains the new Bitnami repository (as we do for the enterprise images), so they don't need to upgrade the chart version they use already and only upgrade the repos (usually users don't upgrade that fast, and any new pull for the images with the old name will fail).

Actions

• Create an extra public values file.
• Document the issue and the extra values file in the official docs.

Sub-tasks

• feat: create extra values file for legacy bitnami repo name #3996
• docs(self-managed): add notes for helm upgrade camunda-docs#6510
• docs: add bitname repo change to the announcements camunda-docs#6595
• Share the details with the support team and related teams.