[bitnami/common] feat: ✨ Show warning when original images are replaced

[javsalgar]

Signed-off-by: Javier Salmeron Garcia jsalmeron@vmware.com

Description of the change

This PR adds a common warning function to be used in NOTES.txt: common.warnings.modifiedImages. This one checks if the Bitnami shipped images are being replaced by images different from the ones set in Chart.Annotations (the ones that have been verified and tested). We want to warn users of the potential risks of this action.

Example of usage in the matomo chart:

{{- include "common.warnings.modifiedImages" (dict "images" (list .Values.image .Values.metrics.image .Values.volumePermissions.image .Values.certificates.image) "context" $) }}

If we change one of the images, we see the following warning:

⚠ SECURITY WARNING: Original containers have been substituted. This Helm chart was designed, tested, and validated on multiple platforms using a specific set of Bitnami and Tanzu Application Catalog containers. Substituting other containers is likely to cause degraded security and performance, broken chart features, and missing environment variables.

Substituted images detected:
  - docker.io/fakebitmame:5.0.3-debian-12-r8

Benefits

Users are more aware of the risks of changing the original images

Possible drawbacks

Potential false negatives/positives. This can be further improved in the future.

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)