Allow Admin to Ensure Images Are Reverified Even if Already Pulled

As an openshift administrator, I would like a way to ensure image pulls reauthenticate with the registry, even if the image is already present and its image pull policy does not require it to re-pull.

This is to enable multitenant environments where different pull secrets are used for different users, and each user shouldn't have access to the others pull secret. Ensuring the image is pulled forces the user to have valid credentials even if the image is already pulled.

This work is being tracked upstream: https://github.com/kubernetes/enhancements/pull/1608