Migrate instance to new underlying physical host.

[amcgregor]

The old machine needs to be decommissioned prior to a move across the country. Either I need to:

• Figure out how to wholesale move the paused VMs from the original Intel host to the new ARM one.
• Rebuild the Docker Compose cluster, restoring Postgres database and public/system uploaded content.

Given the architectural differences, the latter may be more practical. I do have a PostgreSQL dump just prior to freezing the original cluster, as well as a docker cp extracted copy of the public/system folder.

Technically this duplicates or can naturally resolve #4.

Reference.