[UX] Simplify the use of Docker inside containers

[peterschmidt85]

Currently, users have to specify our Docker image, enable privileged, and add start-dockerd manually. The ideal solution would be to allow them to configure this declaratively, e.g., by specifying docker: true, which would handle everything automatically.

While users could still use the old method if they prefer, those who don’t want to would benefit from this new property.

[github-actions]

This issue is stale because it has been open for 30 days with no activity.