sys-apps/ignition: support IPv4 and IPv6

[tormath1]

Do not merge yet. This is for experimental purposes.

Upstream PR: https://github.com/coreos/ignition/pull/2052

Related to: https://github.com/flatcar/Flatcar/issues/1696

• [ ] Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• [ ] Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.
• [ ] http://localhost:8080/job/container/job/packages_all_arches/6293/cldsv/