Get rid of non-security errata html pages

The [AlmaLinux Errata website](https://errata.almalinux.org/) contains static html pages that refer to non-security advisories, like [ALEA-2021:4152](https://errata.almalinux.org/8/ALEA-2021-4152.html). These errata html pages were generated when erratas were first introduced in AlmaLinux, and they shouldn't be there because we only publish erratas for security-related updates to packages.

In order to avoid any potential confusion in our users, we need to get rid of them.