asset/manifests: redact the pull-secret from the cluster object of the install-config
asset/manifests: redact the pull-secret from the cluster object of the install-config

install-config is stores as a config map in the cluster, but the pull-secret in the install-config is a secret that
shouldn't be stores as config map.

The pull-secret is already available to cluster as secret `kube-system/coreos-pull-secret`.

derekhiggins/installer,derekhiggins/installer