Today the ostree CI relies on the buildroot container, cosa and FCOS
all being on the same major.

We will just have to stop testing ppc64le with PXE boot.

HOWEVER: An important thing we could try to do going forward
is again do a build of coreos-assembler using RHEL 9 (or CentOS Stream 9).
We're not actually that far away from this last I tried, particularly
using EPEL content.

It seems like jsonschema in Python 3.12 (in Fedora 39) changed some
implementation details to now use a data structure that doesn't support
deep copying:

    TypeError: cannot pickle 'rpds.HashTrieMap' object

Instead of doing a deep copy, just create a new object from scratch with
the same inputs. The `w` variable might've been for that; it's currently
unused and is an exact copy of `m`.

The Fedora project is moving its images in Quay.io as being the official
ones. Let's use it instead.

Fedora 39 has a newer e2fsprogs whose `mkfs.ext4` now turns on a new
`orphan_file` feature by default. This feature is not supported by the
`e2fsck` currently in RHEL 9.

As mentioned in the comment, ideally we'd use the `mkfs.*` tools
from the target system and not from cosa. But for now, just do some
version testing to know when to opt out to avoid having to add another
`image.yaml` knob for it.

See: coreos#3653 (comment)