add function for handling action links

[andrecedik]

What has changed?

• users can now jump from the plugins page directly into the plugin settings

Please read the commit messages for details.

Things to review

• Link in plugin settings is shown and redirects to the shipcloud settings in WooCommerce

Common things:

• [x] Works fine.
• [x] Changelog written or not needed.
• [ ] No conflict with current branch.

[andrecedik]

There's something weird going on with the PR and its base. I'm closing and reopening it.