feat(ia): settings additional brands

[jaredrethman]

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:

Adds Newspack Multibranded Site wizard to Newspack Plugin Settings Wizard. The majority of functionality is merely a port of the Multibranded plugin.

How to test the changes in this Pull Request:

1. Checkout this branch and build assets.
2. Ensure Newspack Multibranded Site plugin is installed and active.
3. Navigate to /wp-admin/admin.php?page=newspack-settings#/additional-brands
4. Ensure Additional Brands UI loads.
   
5. Perform Tests. For each test confirm; 1. data loaded is correct 2. Data persists between tab changes and page refreshes:
   • Add New Brand - Click "Add New Brand", input desired configuration and click "Save".
   • Edit an existing brand - Click , select "Edit", perform desired edits and click "Save".
   • Delete a brand - Click , select "Delete" and confirm.

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?

[miguelpeixe]

It's looking great! I've encountered a few issues, which I commented inline.

[jaredrethman]

It's looking great! I've encountered a few issues, which I commented inline.

@miguelpeixe thanks for the thorough review. I've refactored & fixed most of your feedback. Let me thoughts on #3462 (comment)

[miguelpeixe]

Thank you for all the revisions! It's looking great!

One small adjustment is needed for the new error handling. It's not getting cleared:

After receiving an error due to duplicate slugs, I adjust my slug name and click save. If edit a brand - the same or any other - the error message is still there.

[jaredrethman]

Thank you for all the revisions! It's looking great!

One small adjustment is needed for the new error handling. It's not getting cleared:

After receiving an error due to duplicate slugs, I adjust my slug name and click save. If edit a brand - the same or any other - the error message is still there.

This shouldn't be happening, it should be clearing automatically after a successful subsequent request. I can reproduce, looking into why this is happening, will revert shortly.

[jaredrethman]

Thank you for all the revisions! It's looking great!
One small adjustment is needed for the new error handling. It's not getting cleared:
After receiving an error due to duplicate slugs, I adjust my slug name and click save. If edit a brand - the same or any other - the error message is still there.

This shouldn't be happening, it should be clearing automatically after a successful subsequent request. I can reproduce, looking into why this is happening, will revert shortly.

I was mistaken, at one stage this one the plan - at the time it wasn't feasible. Anyway - I have added code that will reset the error on location change 920a27a

[miguelpeixe]

Thanks for the revisions, Jared! Working great now 💯