feat: add quick actions edit mode

[thomasguillot]

All Submissions:

• Have you followed the Newspack Contributing guideline?
• Does your code follow the WordPress' coding standards and VIP Go coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

NOTE: This is an experiment—feel free to disregard this PR if you find the implementation lacking.

This PR improves the Quick Actions section in the dashboard and allows publisher to custom them via drag and drop.

• Added a maximum of 3 active Quick Actions with drag-and-drop functionality
• Wobble animation during editing and improved button styles
• Added "Reset to default" option and proper cancel functionality

newspack-edit-quick-action.mp4

How to test the changes in this Pull Request:

1. Switch to this branch
2. Locate the Quick Actions section in the dashboard.
3. Edit the actions, using drag and drop. Remove/add, play with it.
4. Does it save properly (refresh the page to check)
5. Restore to default and save (refresh the page to check)

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran tests with your changes locally?

[leogermani]

I love this. I'd say let's wait for IA to be deployed, since testing is already underway, and we can circle back to this