PullSecrets configuration option for controller container image

[mkaesz-wandb]

Note:

This ticket is only targeting the controller. There will be a separate ticket for the W&B application.

Situation:

Customers deploy W&B in airgapped environments. This means that they put the W&B container images into an onprem registry, like Artifactory. To pull the images from that registry, you need to authenticate. Kubernetes has a functionality called ImagePullSecrets for that.

Need:

We need to add the configuration option so that customers can configure multiple image pull secrets in the values.yaml.

Example:

The Redis Helm chart allows to configure a list of secrets in the values.yaml.

The YAML snippet is prepared here and here.

The actual inclusion of the snippet happens here.