Article layout

Tweaks https://gitlab.com/gitlab-com/gitlab-docs/merge_requests/131:

• add the article-metadata div to the default layout, not to a new layout
• create a conditional to add the article-metadata div to the layout
• use the flex display CSS property order to change the order of the article-metadata div to make it display just after the h1
• revert .gitlab-ci.yml before merging

Closes #157 (closed)

After this MR: => https://gitlab.com/gitlab-org/gitlab-ce/issues/42831

• update all articles frontmatter
• update "writing documentation" doc

Review Apps: http://article-layout-1.178.62.207.141.xip.io/ce/ci/examples/laravel_with_gitlab_and_envoy/index.html

---

Article frontmatter: https://gitlab.com/gitlab-org/gitlab-ce/commit/97e9d77ab9365504299481a1b93876ed3389ad2c

---
author: John Doe
author_gitlab: jonhdoe
level: intermediary
type: tutorial
date: 2018-01-01
---