storage: Change order of actions for a blank disk

[garrett]

Creating a partition table on an empty disk should be the default action.

We might even consider promoting the action to a button, as you really can't do much with a disk by default without creating a partition table (in most cases).

(Without a partition table, you can add a disk to some kinds of RAIDs, such as btrfs. You can also use it for raw storage for a database. But when Cockpit is used in Anaconda, people generally won't be doing that by default. And you could still add a disk with a partition table to RAIDs and such; it'd just remove the partition table if needed, I think, so it shouldn't be harmful even if someone does add one.)

Additionally, it's not "Unformatted data", it's a blank disk. It could say "Unformatted" or "Empty disk" or something like that.

[garrett]

Related: #19882 (which is a larger PR and has several features in addition to this)