Add status to support bundles for storage specific stats

[leftwo]

The zone-bundle command collects some data when requested and/or when a
zone is shutdown. We should add crucible DTrace stats or other storage specific
breadcrumbs to that collection process.

[bnaecker]

I've not yet found a good way to add zone-specific commands to this output. One path might be to inject the data you care about into the logs themselves, which are always collected. Another could be for the zone image itself to include a script or program at a well-known location, which zone-bundle attempts to execute when it runs. I'm sure there are other, better ideas too!

[leftwo]

For a downstairs zone and the pantry zone, we do have some dtrace scripts inside the zone that we can call on.
For a propolis zones, yeah, I've not figured out how to get scripts inside those zones.