Cirrus CI: Revert "neuter cirrus" and use FreeBSD 12.1 stable image
Cirrus CI: Revert "neuter cirrus" and use FreeBSD 12.1 stable image

This reverts commit 139c2b38a0a4378a0458dc03b0ac0631acf6229e and switches to a
stable FreeBSD release and adds comments to the CI config for maintenance.

Co-authored-by: Chris K <84a516841ba77a5b4648de2cd0dfcb30ea46dbb4@chrisko.ch>
Signed-off-by: Daniel Maslowski <59bd0a3ff43b32849b319e645d4798d8a5d1e889@orangecms.org>

hugelgupf/u-root,hugelgupf/u-root,u-root/u-root,u-root/u-root,u-root/u-root,hugelgupf/u-root,hugelgupf/u-root