Support for Local Storage in Omicron

[leftwo]

Tracking issue for support of Local Storage in Omicron.

We have a few things to finalize before we can build this into Omicron, including discussions in rfd 590 PR here

From this, we will possibly have some instance lifecycle changes, and possibly new instance states.

More to come here as things develop.

[leftwo]

Building a rough list of control plane features, this section subject to edits.

• When expunging a disk, instances with local storage need to change state to reflect the failed nature of the local storage.