Move EE-specific `.gitlab-ci.yml` content to `ee/.gitlab-ci.yml` with an `include` directive
(Perhaps once https://gitlab.com/gitlab-org/gitlab-ee/issues/5078 is resolved)
EE has a number of changes in .gitlab-ci.yml
that could be extracted out into a separate ee/.gitlab-ci.yml
file, using the include
directive newly added to GitLab. This would make maintenance and CE->EE merges easier.
/cc @rymai