Add docs on CI caching
What does this MR do?
Document thoroughly how CI cache works.
Preview
http://ce-docs-ci-caching.178.62.207.141.xip.io/ce/ci/caching/index.html
What are the relevant issue numbers?
Closes #32515 (closed),#18945 (closed), gitlab-runner#1621 (closed)
TODOs
-
Consolidate info from https://gitlab.com/gitlab-org/gitlab-ce/issues/32515 -
Consolidate info from gitlab-runner#336 -
Expose document to ci/README.md
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Document default cache:key
https://gitlab.com/gitlab-org/gitlab-ce/issues/18945 https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17595 -
Merge first: gitlab-ci-yml!147 (merged) -
Merge first: gitlab-runner!733 (merged)
Edited by Achilleas Pipinellis