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:

Closes https://app.asana.com/0/1205919985867982/1209710969266199

This PR merges the email settings from Audience > Transactional Emails and Newspack > Settings > Emails into the settings page for the latter.

How to test the changes in this Pull Request:

1. As admin, navigate to Newspack > Audience
2. Verify there is no longer a Transactional Emails tab present
3. Navigate to Newspack > Settings > Emails
4. Verify all newspack email templates are present here, including all of the templates shown in the screenshot.
5. Smoke test the various templates, including:

• Editing
• Resetting
• Toggling

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?