chg: doc: Update CVE checklist

Account for the recent nomenclature change in the CVE checklist.

Add a placeholder for a link to an Earliest Notification draft for every
vulnerability handled.

Use consistent Markdown reference names for all URLs in the summary
table.  Provide a template for all URLs to indicate naming expectations.

Merge branch 'michal/update-cve-checklist' into 'main'

See merge request isc-projects/bind9!11313