docs/setup.md should contain a disclaimer to run Docker in root, not rootless

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Description

This isn't much of a bug/feature request, but it is an important distinction.

cgroups will not work if the Docker is running rootless. It will just result in an error stating that cgroups is not writable.

Maybe it's worth adding a disclaimer for this, or a workaround if the user wishes to run in rootless, but that's just my 2 cents.

[arty-hlr]

@returnofblank What would be the workaround in this case? I just had this problem.

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My workaround was just running Docker with root. Maybe there's some way to get it working with Rootless, but I didn't bother finding any.