Create global variables for SMTP configuration

[pvannierop]

          Ok the most simple solution would be to write this entry in base.yaml like so:

kratos:
  _install: true
  _chart_version: 0.43.0
  _extra_timeout: 0
  ....
  kratos:
    courier:
      smtp:
        from_address: [email protected]

However, since SMTP settings are also used by MP (and possibly other services), we should consider defining this as global properties and inject this in the set: section of helmfile where needed.

Originally posted by @pvannierop in #266 (comment)

[pvannierop]

Appserver now also has SMTP credentials.