Custom domains: support making a domain the site's primary domain

[jaclync]

In design i3 VyLr7LvKodHE4kINfBE7Lw-fi-1709%3A93503, we're adding an action to mark a domain as the site's primary domain. Also, we are going to show if a domain is the site's primary domain.

Design: VyLr7LvKodHE4kINfBE7Lw-fi-682%3A37529

• [ ] Add a badge to a custom domain row if it's the site's primary domain
• [ ] Add an ellipsis menu to show an action sheet for making a domain the site's primary domain
  • [ ] UI
  • [ ] Networking & Yosemite layer changes

[peril-woocommerce[bot]]

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[peril-woocommerce[bot]]

	Fails
:no_entry_sign:	Please add a feature label to this issue. e.g. 'feature: stats'

Generated by :no_entry_sign: dangerJS