Add a basic support for building RHEL-8.9 and RHEL-9.3 images with
composer.
Add 8.9 and 9.3 repositories to the multitude of places where we have
them.
Generate image test manifests for 8.9 and 9.3. No functional testing is
added for 8.9 or 9.3 at this moment.
This change unblocks the RHEL Gating (since unit tests are currently
failing on 8.9 and 9.3 as on unknown distribution).
Related to https://issues.redhat.com/browse/COMPOSER-1924
Signed-off-by: Tomáš Hozza <thozza@redhat.com>
