Reduce duplication between .gitlab/ci/release-environments/main.gitlab-ci.yml and .gitlab/ci/review-apps/main.gitlab-ci.yml

The following discussion from !110712 (merged) should be addressed:

• @rymai started a discussion:

  thought: The review-build-cng-env and review-build-cng jobs in this file are almost identical to .gitlab/ci/review-apps/main.gitlab-ci.yml, so I think we could probably extract these two jobs in a new .gitlab/ci/cng/main.gitlab-ci.yml shared file. This could be a follow-up.