* Change public accounts pages to mount the web UI
* Fix handling of remote usernames in routes
- When logged in, serve web app
- When logged out, redirect to permalink
- Fix `app-body` class not being set sometimes due to name conflict
* Fix missing `multiColumn` prop
* Fix failing test
* Use `discoverable` attribute to control indexing directives
* Fix `<ColumnLoading />` not using `multiColumn`
* Add `noindex` to accounts in REST API
* Change noindex directive to not be rendered by default before a route is mounted
* Add loading indicator for detailed status in web UI
* Fix missing indicator appearing while account is loading in web UI
* Redesign landing page (again)
* Move login form in small version to the right column
* Display closed registrations message
* Add site setting for the hero image
* Fix test
* Increase spacing, maximum width, change call to action section
They were redundant, and also had a inconsistency; the button for
"other instances" had an icon for the external link in "more" page, but
it didn't in the other pages.
This unifies the implementation, and the external link icon is now shown
in all the about pages.