Jetpack Onboarding: Improve Business Address form fields

[tyxla]

In order to make the business address form less USA-centric and improve the labels, let's:

• Rephrase the state field as "state/region/province"
• Add a country field
• Use sentence case

A bonus idea by @rickybanister is to have an address component that we can reuse in such cases.

For more information see p6TEKc-1Rd-p2

[tyxla]

This is being addressed by several PRs:

• REST API: Add Country field to Business Address onboarding step jetpack#8874 - adds support for the Country field to the REST API endpoint
• Jetpack Onboarding: Add country field to business address step #22580 - adds the country field to the business address form (and settings schema)
• Jetpack Onboarding: Improve Business Address field labels #22581 - improves the field labels and makes them more consistent