Backport CNG and Omnibus changes to 17.6 and 17.5 to support Internal Release

Context

There is an emerging need to build and deliver private packages to remediate GitLab Dedicated instances, the internal nature of such packages is required to prevent disclosing the vulnerability and to make it independent from the GitLab patch releases.

After #20653 (closed) and #20654 (closed), it is possible to trigger CNG and Omnibus pipelines to build Internal Release packages. We need to backport the change to older stable branches to be able to build for older versions.

MRs to backport

• CNG:
  • gitlab-org/build/CNG!2117 (merged)
• Omnibus:
  • gitlab-org/omnibus-gitlab!8058 (merged)
  • gitlab-org/omnibus-gitlab!8051 (merged)
  • gitlab-org/omnibus-gitlab!8045 (merged)
  • gitlab-org/omnibus-gitlab!8075 (merged)

Exit Criteria

• All required MRs are backported to 17.6
• All required MRs are backported to 17.5

Backports

17.6

• CNG: gitlab-org/build/CNG!2199 (merged)
• Omnibus: gitlab-org/omnibus-gitlab!8137 (merged)

17.5

• CNG: gitlab-org/build/CNG!2200 (merged)
• Omnibus: gitlab-org/omnibus-gitlab!8138 (merged)