Implement the simple version of publishing.
This publishes all available variants, no publish dialog, also no unpublish button, as we are still missing the button drop-up UI.
Also, notice publish API does not support segments, and I think this needs to be changed to a different model like:

{
    variants: [
        {
            culture: string | null
            segment: string | null
        }
    ]
}

This would be futureproof, and allow for even more props pr. variant and as well using null for invariant or not-segmented seems more correct to me.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (minor updates related to the tooling or maintenance of the repository, does not impact compiled assets)

Motivation and context

How to test?

Screenshots (if appropriate)

Checklist

• If my change requires a change to the documentation, I have updated the documentation in this pull request.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.