[dev]: Refactor Checkout

[sirugh]

Description

Refactoring of checkout components, including updating unit tests. Notably:

• Removed SubmitButton in favor of just using the Button component directly.
• Removed the unused ResetButton.
• Address Form Refactor
  • fixed bug in checkout reducer where street address was not saved
• BraintreeDropin Refactor
  • The conversion to the mount/unmount logic required some...interesting code. Check out the useEffect in the component and see how I had to use a local variable to ensure we teardown/error properly.
• Payment Form Refactor
  • identified a "bug" where informed updates state if initialValues are used causing multiple renders.
• Form Refactor
  • The parent form is now split into multiple function components. Should we move these into a Form/ directory and split them out into individual files?

Related Issue

Closes #1294.

Verification Steps

1. Go to the checkout form and step through it. Everything should work including all validation, etc.
2. Try doing the checkout form out of order.
3. Try quickly opening and closing sub-forms such as the payments form.
4. Make sure form state is used appropriately. Does it remember address? Does it remember last choices such as "use same as shipping address", etc?

How have YOU tested this?

Lots of manual testing through different scenarios. See above.

Screenshots / Screen Captures (if appropriate):

Proposed Labels for Change Type/Package

• major (e.g x.0.0 - a breaking change)
• minor (e.g 0.x.0 - a backwards compatible addition)
• patch (e.g 0.0.x - a bug fix)

Checklist:

• I have updated the documentation accordingly, if necessary.
• I have added tests to cover my changes, if necessary.

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[sirugh]

A wild hook appears!

[jimbo]

Good comment. I'm not surprised, though; Informed implements change publishing manually, so they're not doing hooks + context in any sort of optimal way.

[sirugh]

The parent form is now split into multiple function components. Should we move these into a Form/ directory and split them out into individual files?

[sirugh]

@jimbo says he prefers flat structure. I like nested, for things that are specific to a parent and won't be shared. 🤷‍♂

[supernova-at]

The parent form is now split into multiple function components. Should we move these into a Form/ directory and split them out into individual files?

We should definitely split them out into individual files, as per existing convention. I do like the idea of a Form/ directory personally - especially since we have a Receipt directory within Checkout already.

[supernova-at]

@jimbo says he prefers flat structure. I like nested, for things that are specific to a parent and won't be shared. 🤷‍♂

[jimbo]

We should never have had a Receipt folder either—last year we had a few contributors who didn't like to follow conventions. 😉

Honestly though, if you guys prefer to nest folders in places with a lot of files like this, I'm fine with it. Just don't go overboard.

[jimbo]

@sirugh Looks good. A couple remaining small items if you'd like, but this is basically ready. 👍

[sirugh]

@jimbo feedback addressed! If this is good to go please put it in Ready for QA :)