Build Omnibus package for release environment

What does this MR do and why?

Build Omnibus package for release environment

As we are going to use GET for release environments, Omnibus package is required. Details of this implementation:

• Add two new job release-environments-build-omnibus-env and release-environments-build-omnibus to the release environment pipeline
• Since we are testing, the build jobs don't block the pipeline (allow_failure: true)
• This implementation is cloned from .gitlab/ci/qa-common/omnibus.gitlab-ci.yml, with minimal changes. The reason why I clone, instead of using job template:
  • They are two different implementations, which are coincidentally identical
  • Making the jobs in the release-environments pipeline depend on QA templates doesn't make sense, and the templates may change without us knowing
  • Changing the QA templates may have unknown side effect, since these templates are used in many other places/repositories

References

Ref: gitlab-com/gl-infra/delivery#21244 (closed)

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.