Feature: Select all variants option in publishing dialogs

[madsrasmussen]

Description

This PR adds a "Select all" option to the "publishing" dialogs

• Save
• Save and Publish
• Schedule
• etc.

What to test:

• Make sure that when selecting all, all allowed variants are selected
• Make sure only the allowed languages are chosen

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)