SLT-1193: Remove the deprecated mailhog service from Drupal and Front-end charts

[k4lv15]

Mailhog got deprecated in #478 and replaced by mailpit. This PR removes maillog from SIlta's helm charts completely.

Changes proposed:

• Drupal chart: SLT-1193: Drupal chart: Remove deprecated mailhog service from the chart drupal-project-k8s#748
• Frontend chart: SLT-1193: Frontend chart: Remove deprecated mailhog service from the chart frontend-project-k8s#146
• Remove locally forked mailhog chart as it's not needed anymore
• Remove codecentric helm repo reference from CCI config

IMPORTANT NOTE! This is a breaking change!
If you're overriding default mailhog configuration in your helm chart value override files (like silta/silta.yml etc)., make sure to switch to mailpit, otherwise helm chart installation will fail with schema validation errors. Also note that old mailhog URL is still working but redirected to /mailpit

I.e, if you had mailhog enabled:
Before: in silta/silta.yaml

mailhog:
  enabled: true

After: in silta/silta.yaml

mailpit:
  enabled: true

[Copilot]

Pull Request Overview

This pull request removes the deprecated Mailhog service from the Helm charts and Drupal configurations in favor of using Mailpit. The key changes include, the complete removal of Mailhog template files and configurations, updates to value and schema files to exclude Mailhog settings, and the corresponding cleanup of conditional logic in Drupal templates and CI configuration.

Reviewed Changes

Copilot reviewed 34 out of 34 changed files in this pull request and generated no comments.

File	Description
forked/codecentric/mailhog-5.1.0/*	Removed all Mailhog-related chart templates and configuration files
drupal/*	Removed Mailhog service configuration and references from Drupal files
.circleci/config.yml	Updated CI configuration to remove Mailhog-related repository addition

Comments suppressed due to low confidence (2)

drupal/values.schema.json:634

• The 'mailhog' property is removed from the JSON schema. Please ensure that any associated documentation or migration guides are updated to reflect this breaking change.

"mailhog": {

drupal/templates/smtp-secret.yaml:1

• The removal of '.Values.mailhog.enabled' from the secret condition ensures that Mailhog secrets are no longer created. Please verify that this change aligns with the intended service deprecation strategy.

{{- if or .Values.mailpit.enabled .Values.smtp.enabled }}

[k4lv15]

Postponed until mailhog is properly deprecated in #484, marking as draft for now.