Kubernetes service namespace

This MR updated documentation with information about auto-generated namespace: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10438.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/30445

added 261 commits

• 731cc620...33a25e0f - 260 commits from branch master
• 63d6edf1 - Update Kubernetes namespace documentation

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added 1 commit

• ee8d9ac8 - Move kube namespace section to the variables one

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approved this merge request

Thanks @ayufan :) I moved it to the variables section instead :)

enabled an automatic merge when the pipeline for ee8d9ac8 succeeds

merged

mentioned in commit 631bc875

Picked into 9-1-stable, will go into 9.1.0-rc6

mentioned in commit 91b1f03d