Create DiskArchiver for SPS

[blinkdog]

This PR creates a DiskArchiver component/module to replace the one in jadeite, for use at SPS.

Motivation:

• The jadeite DiskArchiver works, but is relatively slow at finalizing disks, especially large disks.
• This wasn't a big problem when the archival disks were ~2-6 TB, but now that we're deploying 16 TB disks, it could become an operational issue.
• Moreover, the way metadata is created at the end puts all of the metadata in one large JSON object. Again, less of a problem when archival disks were ~2-6 TB, but now with 16 TB disks, it can become an operational issue. (Also; who wants to load a huge multi-GB single JSON object?)
• The new DiskArchiver is intended to solve all of these issues, and also provide new data safety checks using hardware metadata.
• In particular, we'd like to capture the hardware metadata at the time the disk is used for archival purposes. We'd also like to store that in a database, make it queryable, and ensure that a serial number is not reused "too soon" (i.e.: within the same retro disk season).