Container image visibility

Description

Docker container images be public or private.

Proposal

I propose a function in settings to set container images visibility (Public, Internal, Private). It's good for projects, that have public images and don't require login to get the image.

Links / references

Docker hub

Quay

Documentation blurb

1. The problem is that there isn't a visibility set for container images. Some users would like to refine it to have images be public, internal or private.
2. I suggest create a special tab for registry in project's settings and let users customise their visibility and also set default visibility based on project's visibility on creation.
3. Every container registry that I've seen supports this and I would like to see it in GitLab.