Domains: Add make primary domain functionality to new site domains view

[eltongo]

Changes proposed in this Pull Request

This adds the ability to set domains as primary in the new site domains view.

Testing instructions

• Go to /domains/manage/
• Test 'Make primary domain' button works as expected

Also, set state.changePrimaryDomainModeEnabled to true, and:

• Verify the radio button shows correctly
• Verify on free sites, the plan upsell appears
• Make sure choosing any domain makes that domain primary (when eligible)

[matticbot]

Test live: https://calypso.live/?branch=add/primary-domain-new-design

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

Sections (~341 bytes added 📈 [gzipped])

name     parsed_size           gzip_size
domains      +2445 B  (+0.2%)     +341 B  (+0.1%)

Sections contain code specific for a given set of routes. Is downloaded and parsed only when a particular route is navigated to.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[hambai]

Looks good. I took the liberty of updating the PR to enable the "Change primary domain" button in the primary domain header card.

[a8ci18n]

This Pull Request is now available for translation here: https://translate.wordpress.com/deliverables/4112146

Thank you @eltongo for including a screenshot in the description! This is really helpful for our translators.

[a8ci18n]

Translation for this Pull Request has now been finished.