Introducing initial changes needed for IPU 9 -> 10 to prevent abouvious
crashes and inhibitors:
* Extend the list of supported source versions for the upgrade by el9
* Define upgrade paths for IPU 9 -> 10
* Add Python path for el 10 (py 3.12)
* Introducing el9toel10 repository
  created .gitkeep files inside empty dirs

NOTE:
    Enable upgrade from RHEL 9.4 & 9.5 to RHEL 10.0 for now. For the
    experiment purposes. These will not be supported for the upgrade at all,
    but to make testing and experimentations easier, allow it for now.

TODO:
* add RHEL 10 product certificates
* add RHEL 10 GPG keys

SPEC files has been updated and polished to be more friendly when
keeping suppoer for building in EL 7, 8, and 9. Also Makefile
contains some initial changes But keeping the full solution for a
separate commit.

Packit configuration has been updated to start building for
epel-9-x86_64 buildroot.

Adding RHEL 9 containers so we can start to test & build packages
in RHEL 9 environemnt.

Since `python3-virtualenv` package is not available in the RHEL 9 UBI,
a workaround is introduced `make install-deps-fedora`, which is used by
the testing containers. If not able to install the package, `pip install
virtualenv` is used as a fallback as this is working in the image.

The relatively recent Python version used in the container means there
is also a relative recent Pylint verision, which introduces 2+ new
checks.

Currently we use frozen python modules due to compatibility with
python2. As we want to keep now still Py2 support due to RHEL 7
for a while, we do not want to simply use the newest versions of
current modules. However, with Python 3.12 we see it's really old
and some of old versions (like pytest) does not work as expected.

For that reason, adding conditional requirements for pytest. I chose
now to stick with pytest 6.2.5 which is compatible with Python3.6+
(due to RHEL 8).

Most likely we will need to revise other requirements too, but I focused
now just on obvious issues.

* Add RHEL 10.0 Beta product certificates
* Add FAKE RHEL 10.0 product certificates
  * productions certificates for RHEL 10 has not been generated yet,
    so adding faked certificates for now. In this part development
    it's expected to test upgrades using internal custom repositories
    only. Until the testing with RHSM certs are not needed yet.
    But they will have to be updated for sure before the release.
* Add RHEL 10 (+Beta) RPM-GPG-KEY-redhat-release
  * updated key from RHELBLD-15138 attached

* TODO: replace faked RHEL 10 product certificates by real ones when
  available

Co-authored-by: Michal Reznik (mreznik) <mreznik@redhat.com>
Co-authored-by: Matej Matuska <mmatuska@redhat.com>

The util-linug RPM is not installed automatically as a dependency
when:
  * upgrading 9 -> 10
  * or when dnf is configured to: install_weak_deps=False
    (affecting all upgrade paths)

Missing util-linux package leads to error due to missing `su` command
inside the container.

jira: https://issues.redhat.com/browse/RHEL-43978

Implementation of processing versions inside commands/command_utils.py
has been bugy. One of function returned string instread of list
which led to the situation that only the first character has been
returned instead of the first chunk. This has been ok for releases
where major version is just one decimal. However since el 10 it has
been buggy and generated set envar:
    LEAPP_IPU_IN_PROGRESS=9to1
instead of
    LEAPP_IPU_IN_PROGRESS=9to10

Now it should be working correctly again.

jira: OAMG-11260

Based on the bug fixed in the previuos commit, we are rather adding
unit-tests for get_major_version() function in common libraries,
to prevent possible issues in future there too.

Note that the data is artificial, meaning it's not generated through
repomapping generator and therefore not verified by it against the
source of truth. The assumption is that the repos will be similar to how
they are on RHEL 9 and are basically copied (redundant channels and rhui
repos are dropped).

They are not owned by any package and can dynamically grow to
a huge amount of files causing hitting open files limit

The RPM DB has been moved from /var/lib/rpm to /usr/lib/sysimage/rpm
in RHEL 10. Apply the change and create symlink in the original
path to the new one as expected.

Also rebuild the RPM DB to ensure it's compatible with the new RPM
version. Previously the RPM DB was being rebuilt during IPU 8 -> 9.
However after discussion with RPM SMEs it has been decided that this
is actually very reasonable to do always. So applying for any upgrade
path but IPU 7 -> 8 (let's do not change this one so much when it's
kind of finished).

Co-authored-by: Matej Matuska <mmatuska@redhat.com>

No keys will be obosoleted, however it's expected to define the list.

The `onerror` argument of shutil.rmtree is deprecated and replaced by
`onexc` since Python 3.12. It accepts callback with the same arguments
except for the last one which is now a subclass of `BaseException`. Our
callback `libraries.utils.report_and_ignore_shutil_rmtree_error` is thus
modified accordingly.

Originally the actor used distutils.version.LooseVersion to detect
newest version of installed kernel package inside target userspace
container. But the distutils python module has become deprecated
and we should not use it anymore in Python 3.12+.

However, we do not expect to see multiple versions of kernel present
inside the target userspace container as the container is created
during the IPU process from scratch (always). Considering the presence
of multiple kernels to be sign of error, which could negatively affect
also additional actions later.

Updated the solution, raising an error if multiple kernels are detected
inside the container. As we expect one kernel only, no need to compare
versions of particular possible kernel packages.

Note there are now just these cases when this could happen:
  * a third party package is required to be installed inside the
    container
  * an explicit requirement to install particular version of container
    is made by a custom actor