[deer-wmde]

• adds two valkey deployments to the app-of-apps
• the default chart ref is this tag: https://github.com/wbstack/valkey-helm/releases/tag/valkey-0.12.1
• values for valkey deployments are read from deploy repository
  • first production, then env overrides
    • seems like this "just works" - but in the back of my head there is some memory of this behaving a bit differently than helmfile

https://phabricator.wikimedia.org/T442989