switch installers to bookworm

as part of the %Debian 12 bookworm upgrade milestone, we should switch the installers to setup only new bookworm machines from now on.

• ganeti: @lavamind added this to hiera/common.yaml, but maybe it should be made upstream as well:

  ganeti::debootstrap_variants:
    bookworm:
      suite: "bookworm"

  • @lavamind fix Puppetfile to point at https://gitlab.com/shared-puppet-modules-group/puppet-ganeti/-/commit/ff3814b6572dc03621fcd6027d23c89f55a7fe8f
• wiki instructions (wiki-replica@c97207ab)
• fabric_tpa