Ensure that custom AlmaLinux security advisories are fully compliant with current advisories

[javihernandez]

AC:

• updateinfo.xml data is properly generated, is compliant with current content and dnf updateinfo is able to take it into account when listing advisories
• OVAL related data is generated and is fully compliant with current security advisories
• Data in errata.json, errata_full.json, and errata.rss is fully compliant with current content
• The custom security advisory is displayed properly in errata.almalinux.org
• AlmaLinux osv-database is filled in as expected