x86, arm: create new rhel 9.8, 10.2 specific machine types

JIRA: https://issues.redhat.com/browse/RHEL-105826
JIRA: https://issues.redhat.com/browse/RHEL-105828

Add new downstream machine types:

• virt-rhel9.8.0, virt-rhel10.2.0
• pc-q35-rhel9.8.0, pc-q35-rhel10.2.0

Signed-off-by: Sebastian Ott sebott@redhat.com