[DOCUMENTATION] Provide Scan-Guidance for Scan-Content Created Prior the Release of RHEL 8.8

[ferricoxide]

Per the closure-note for the ash-linux-formula project's plus3it/ash-linux-formula/issues/452, some scanners are using out-of-date hardening-guidance and associated testing. Per updated guidance from Red Hat, RHEL 8.8 (and 9.2) and higher should be configuring the remember (and retry) PAM pwhistory config-option(s) in the /etc/security/pwhistory.conf file instead of the /etc/pam.d/password-auth and/or /etc/pam.d/system-auth files. Changes made to the the /etc/pam.d/password-auth and/or /etc/pam.d/system-auth files is appropriate for RHEL 8.7 and earlier. If a RHEL 8.x is running versions earlier than 8.8, it's behind on system-patches and in violation of scan-goals.

Update Watchmaker FAQs to reflect this.