Automatic merge from submit-queue

Add a kubectl create secret tls command

A somewhat hasty implementation that enables progress along: https://github.com/kubernetes/kubernetes/issues/20176#issuecomment-177409516, https://github.com/kubernetes/kubernetes/issues/24669, https://github.com/kubernetes/kubernetes/issues/20176#issuecomment-198142836 if associated parties have spare cycles. @kubernetes/kubectl

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