Give a more useful error message on image-mode systems

[jlebon]

Some of the image-mode Fedora variants have started shipping dnf5 for layering purposes (see e.g. coreos/fedora-coreos-tracker#1687). However, this is now confusing users trying to use it client-side: https://discussion.fedoraproject.org/t/f41-kinoite-native-container-dnf5-pgp-key-import-error/131946.

We need better error messages, similar to what was done in dnf4, in dnf5:

• Add detection for ostree-based systems and warn users about losing changes dnf#2053
• Adds checks for container and bootc hosts dnf#2110
• Update bootc hosts message to point to bootc --help dnf#2112

[jan-kolarik]

Hi, I see, thanks for the report. We will plan this to have it resolved soon in a same or similar manner as with the dnf4 reports.