Build Omnibus package for GET Release Environments - 18.0

What does this MR do and why?

Describe in detail what merge request is being backported and why

This MR backports all required MRs to build Omnibus package for GET Release Environments:

• Add a new pipeline type STABLE_BRANCH_SECURITY_... (!8516 - merged)
• Rename pipeline type for release environment (!8521 - merged)
• Set up semver for release environments package (!8525 - merged)
• Fix release environment package name (!8529 - merged)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The original MR has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).

Note to the merge request author and maintainer

If you have questions about the patch release process, please:

• Refer to the patch release runbook for engineers and maintainers for guidance.
• Ask questions on the #releases Slack channel (internal only).