capture catalog content timestamp in `ClusterCatalogStatus`

[grokspawn]

currently, clustercatalog status comes from meta.status.creationTimestamp (ref) which is only set on creation of the pod.

We need a new field that I'll call ClusterCatalogStatus.lastUnpacked here, like CreationTimestamp. And we set this timestamp when we successfully unpack the catalog content (like here)

We than also need to ensure that the print columns prints that field instead of creationTimestamp.

[joelanford]

It is potentially okay to include both timestamps. I think "Age" (from creationTimestamp) is extremely common in column output.