Docs: deprecates articles index
See the general Documentation guidelines http://docs.gitlab.com/ce/development/doc_styleguide.html
What does this MR do?
- Last MR for https://gitlab.com/gitlab-org/gitlab-ce/issues/41138
- Ports https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/16469 to EE
- Adds EE-only articles from the list