Port the Auto DevOps docs from EE (!19539) · Merge requests · GitLab.org / GitLab FOSS · GitLab

Achilleas Pipinellis - OOO until November 25th (parental leave) requested to merge docs/autodevops-multiple-clusters into master Jun 07, 2018

Mostly changes from https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/5578.

Let's port the EE doc so that we can minimize the conflicts.

Edited Jun 07, 2018 by Achilleas Pipinellis - OOO until November 25th (parental leave)