Resolve "Add support for debian 12 (bookworm)"

Description

Dependencies before merge

• Authorize these new os-types to use Debian base image in VAT
• Update global CI/CD vars to include new debian11 and debian12 repos
• This MR to add new debian11 and debian12 repos to Nexus is merged and new repos successfully created.

Risk

Debian pipelines will have to change the os-type in their hardening manifests to be one of either debian11 or debian12. No other pipeline types should be affected.

Rollback Plan

We can rollback the merge if needed.

Testing

Tested in staging, new pipeline flows for debian11 and debian12 both work all the way through.

Closes #873 (closed)