Description
One-shot migration from update-users-groups.pl state to userborn.
Runs once before userborn on systems migrating from update-users-groups.pl. Adds locked stub entries to /etc/{passwd,group,shadow} for every name in /var/lib/nixos/{uid,gid}-map without a live entry so freed ids are not reassigned, and creates previous-userborn.json based on declarative-{users,groups}.
Temporary. Will be removed once the perl implementation has been gone for two NixOS releases.