Prune only those images that are part of the composectl-managed apps #111
Description
Currently composectl update complete --prune command and the corresponding API call prunes all dangles images found on a host/device. As result, if there are some container images pulled by any other than composectl means and those images are not used by any of the composectl-managed apps then such images are pruned once the composectl update process is completed. It can cause a problem for cases when a user or some other software on a host/device pulls some other container images for different than the composectl/compose-app use-cases.
Therefore, it makes sense to allow composectl to prune only those images that are loaded to the docker store by composectl. As result composectl won't interfere with other tools that manages container images.