Need to add a way to report vulnerability via GitHub

[Noam-Alum]

This is a followup to AlmaLinux/almalinux.org#699, we need to choose how we should manage reporting vulnerabilities via GitHub, then add an explanation on how to do so to the vulnerability disclosure policy page on almalinux.org .

@bennyvasquez - "My plan is to add any templates we create (or ask you to) to https://github.com/AlmaLinux/.github so they get populated to all of our repos by default. If we allow private reporting on the repos, though (and this is a note for me/whoever else as an operations need, separate from the rest of this PR) we would need to make sure that it's VERY clear what teams are responsible for each repo and ensure that any reports are escalated immediately."