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/domain_blocks/index.js

@@ -11,6 +11,7 @@ import ColumnBackButtonSlim from '../../components/column_back_button_slim';
 import DomainContainer from '../../containers/domain_container';
 import { fetchDomainBlocks, expandDomainBlocks } from '../../actions/domain_blocks';
 import ScrollableList from '../../components/scrollable_list';
+import { Helmet } from 'react-helmet';
 
 const messages = defineMessages({
   heading: { id: 'column.domain_blocks', defaultMessage: 'Blocked domains' },
@@ -59,6 +60,7 @@ class Blocks extends ImmutablePureComponent {
     return (
       <Column bindToDocument={!multiColumn} icon='minus-circle' heading={intl.formatMessage(messages.heading)}>
         <ColumnBackButtonSlim />
+
         <ScrollableList
           scrollKey='domain_blocks'
           onLoadMore={this.handleLoadMore}
@@ -70,6 +72,10 @@ class Blocks extends ImmutablePureComponent {
             <DomainContainer key={domain} domain={domain} />,
           )}
         </ScrollableList>
+
+        <Helmet>
+          <meta name='robots' content='noindex' />
+        </Helmet>
       </Column>
     );
   }