consider some way to verify target OS compatibility with `install-to-filesystem`

[cgwalters]

I got caught out with using install-to-filesystem --replace=alongside against a Fedora Cloud instance (using btrfs) when targeting Fedora ELN (doesn't enable btrfs).

This problem generalizes to things like installing to LVM but not having LVM in the container, etc.

This is quite tricky to test, but I think we could at least do a dirty sanity check for having the kmod in the target kernel or so?

[cgwalters]

I briefly looked at this recently, and what I think we could do that should work is to use modprobe --dry-run -S $kver_in_container $target_rootfs_type.

[cgwalters]

What I just hit that's related to this is I was trying to do a to-existing-root install of RHEL9 on a RHEL10 target host, and that actually failed in the grub probing because the rhel9 grub failed to parse the rhel10 host filesystem layout. But of course, I think the kernel would also fail to parse (probably?)

[cgwalters]

Thinking about this more...I think we should probably add a stern warning if we detect major OS version skew between the host and the target. Though doing this kind of thing will clash a bit with people wanting to change ID and VERSION_ID for their custom OS builds.