Change public accounts pages to mount the web UI (#19319)

* 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

app/javascript/mastodon/features/follow_requests/index.js

@@ -12,6 +12,7 @@ import AccountAuthorizeContainer from './containers/account_authorize_container'
 import { fetchFollowRequests, expandFollowRequests } from '../../actions/accounts';
 import ScrollableList from '../../components/scrollable_list';
 import { me } from '../../initial_state';
+import { Helmet } from 'react-helmet';
 
 const messages = defineMessages({
   heading: { id: 'column.follow_requests', defaultMessage: 'Follow requests' },
@@ -87,6 +88,10 @@ class FollowRequests extends ImmutablePureComponent {
             <AccountAuthorizeContainer key={id} id={id} />,
           )}
         </ScrollableList>
+
+        <Helmet>
+          <meta name='robots' content='noindex' />
+        </Helmet>
       </Column>
     );
   }