Move chef docs to own section

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For changes to dashboards, please provide a link to the test dashboard for quick reviewing, example:

$ ./test-dashboard.sh example/example.dashboard.jsonnet
Installed https://dashboards.gitlab.net/dashboard/snapshot/pi2uorqB9o1zyMRp5zQimaPd3AGu9jef - example: Overview

Place the above link in the MR description

!>