Feature: add billing address block

[glaubersilva]

Description

Depends on impress-org/givewp#6837

This PR adds a billing address block that allows users to collect the donor's address during the donation process.

Affects

Form Builder

Visuals

Testing Instructions

1. Create a new block;
2. Add the new billing fields block to the form;
3. Save the form;
4. Create a new donation using the form;
5. Check the donations page to make sure that the billing address was saved.

Pre-review Checklist

• Acceptance criteria satisfied and marked in related issue
• Relevant @unreleased tags included in DocBlocks
• Includes unit tests
• Reviewed by the designer (if follows a design)
• Self Review of code and UX completed

---

• To see the specific tasks where the Asana app for GitHub is being used, see below:
  • https://app.asana.com/0/0/1205000286853460

[glaubersilva]

@jonwaldstein I did some cosmetic changes to improve UI feedback and also change a few design details discussed in the comment of this video: https://www.loom.com/share/af7ad39687504710bb838b0b5eb3e5a7

So, it should be ready for a final review now.

[jonwaldstein]

@glaubersilva this is looking great! just a few comments/questions

[glaubersilva]

@jonwaldstein I did the last change you request and open a new PR for the focus ring change. Let me know if there is anything more.

[jonwaldstein]

@glaubersilva great job man!

[rickalday]

Passed manual QA tests