[Feat]: edit-config script should be able to copy stock configs out of a running Docker container.

[Ferroin]

Problem

See https://github.com/netdata/netdata/issues/13389.

Description

In short, handling of stock config files from outside of a container is currently complicated in ways it does not need to be.

Importance

nice to have

Value proposition

Users who mount the config directory on the host will be able to use the edit-config script from the host without significant effort.

Proposed implementation

This will probably need to use a new option to indicate the name of the container to use for copying files. Auto-detection for a container named netdata may be easily doable.

With that info, we can just use docker cp instead of cp and pull the stock configs out of the container directly.

Ideally the implementation should also support podman.