Document environment variables in the helm charts - eg passing external secrets

[pmauduit]

Using the provided values for username/password in case of needed authentication on the remote smarthost:
https://github.com/georchestra/helm-georchestra/blob/main/templates/smtp-smarthost/smtp-deployment.yaml#L49-L55
will force the user of hardcoding sensitive infos directly into the values.yaml file.

Maybe we should remove them from the chart, and document the fact that you can reference a kubernetes secret directly from the extra_env variables ? e.g.:

[...]
    extra_environment:
      - name: RELAY_USERNAME
        valueFrom:
          secretKeyRef:
            key: username
            name: smtp-credentials
      - name: RELAY_PASSWORD
        valueFrom:
          secretKeyRef:
            key: password
            name: smtp-credentials
[...]

[edevosc2c]

It's a tradeoff as a right now between ease of deployment and security. Yes, it's a good idea to use external secret, but this can be cumbersome to implement.

Yes we can document every environment that can be passed manually through external secrets for example.