option to start a local docker registry

[superewald]

Is your feature request related to a problem? Please describe.
I have several projects that build containers within the gitlab ci workflow. Some of them use the gitlab registry (in particular the $CI_REGISTRY, $CI_REGISTRY_USER and $CI_REGISTRY_PASSWORD variables) to push and pull specific layers to implement some kind of "caching".

Describe the solution you'd like
A cli option for gitlab-ci-local which will start a local docker registry and populate the $CI_REGISTRY variable to all gitlab-ci-local managed containers.
For eg. gitlab-ci-local --registry would

• start a https://hub.docker.com/_/registry container
• add an override for $CI_REGISTRY variable for other containers
• execute gitlab-ci-local main logic/pipelines
• stop the registry container before exiting

Describe alternatives you've considered
As described in the docker-in-docker-build-with-local-registry example, it is currently required to start and stop a local docker registry manually. That is inconvenient as gitlab-ci-local should not require additional setup commands to run for cases which are supported by the original gitlab-runners in my opinion.
Also it makes scripting with gitlab-ci-local a bit more verbose and adds a source of failure.

Additional Context
I'm using buildah and podman but the same scenario should apply to docker afaik.