Add explore page to web UI (#17123)

* Add explore page to web UI

* Fix not removing loaded statuses from trends on mute/block action

app/javascript/mastodon/features/explore/links.js

@@ -0,0 +1,48 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import Story from './components/story';
+import LoadingIndicator from 'mastodon/components/loading_indicator';
+import { connect } from 'react-redux';
+import { fetchTrendingLinks } from 'mastodon/actions/trends';
+
+const mapStateToProps = state => ({
+  links: state.getIn(['trends', 'links', 'items']),
+  isLoading: state.getIn(['trends', 'links', 'isLoading']),
+});
+
+export default @connect(mapStateToProps)
+class Links extends React.PureComponent {
+
+  static propTypes = {
+    links: ImmutablePropTypes.list,
+    isLoading: PropTypes.bool,
+    dispatch: PropTypes.func.isRequired,
+  };
+
+  componentDidMount () {
+    const { dispatch } = this.props;
+    dispatch(fetchTrendingLinks());
+  }
+
+  render () {
+    const { isLoading, links } = this.props;
+
+    return (
+      <div className='explore__links'>
+        {isLoading ? (<LoadingIndicator />) : links.map(link => (
+          <Story
+            key={link.get('id')}
+            url={link.get('url')}
+            title={link.get('title')}
+            publisher={link.get('provider_name')}
+            sharedTimes={link.getIn(['history', 0, 'accounts']) * 1 + link.getIn(['history', 1, 'accounts']) * 1}
+            thumbnail={link.get('image')}
+            blurhash={link.get('blurhash')}
+          />
+        ))}
+      </div>
+    );
+  }
+
+}