RHEL 8.8 will be added as parallel with RHEL 8.6 until packaging
site gives green light to remove the older Red Hat version.
Removing also some obsolete package installations.
Task-number: QTQAINFRA-5600
Change-Id: Ie77500a805a89db9019b5347539e662bc016af59
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Jukka Jokiniva <jukka.jokiniva@qt.io>