[sled agent] Should be capable of parsing, formatting M.2 drives

[smklein]

Follow-up to https://github.com/oxidecomputer/facade/issues/11

The sled agent should be capable of parsing and formatting M.2 drives to have the expected format we want.

• Sled Agent should be able to parse M.2 drives with an oxi_ (internal) prefix: Parse M.2s, propagate parent information about zpools to Nexus #2708
• Sled Agent should be able to format the expected partitions onto an M.2
• Sled Agent should be able to configure a dump device on the partition dedicated for it
  • See also: [sled agent] every gimlet should have a dump device #2450
• Sled Agent should be capable of utilizing swap space on the M.2 dump device #2858

Priority should be around "parsing", as presumably they'll be formatted during factory install, but they are a FRU, so it's possible we'll need to dynamically format them as they're replaced.