Add a 3.18 RN

[Lennonka]

We need a release note saying that "the persistence data will be available in a future version of subscription-manager".

We do not know exactly what version, but it should be in the relatively near future (months scale, not years) since the blocker is SELinux. Pending PR: candlepin/subscription-manager#3684

RH Jira: https://issues.redhat.com/browse/RHEL-108712

Originated in #4605 (review)