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/statuses.js

@@ -0,0 +1,48 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+import ImmutablePropTypes from 'react-immutable-proptypes';
+import StatusList from 'mastodon/components/status_list';
+import { FormattedMessage } from 'react-intl';
+import { connect } from 'react-redux';
+import { fetchTrendingStatuses } from 'mastodon/actions/trends';
+
+const mapStateToProps = state => ({
+  statusIds: state.getIn(['status_lists', 'trending', 'items']),
+  isLoading: state.getIn(['status_lists', 'trending', 'isLoading'], true),
+});
+
+export default @connect(mapStateToProps)
+class Statuses extends React.PureComponent {
+
+  static propTypes = {
+    statusIds: ImmutablePropTypes.list,
+    isLoading: PropTypes.bool,
+    multiColumn: PropTypes.bool,
+    dispatch: PropTypes.func.isRequired,
+  };
+
+  componentDidMount () {
+    const { dispatch } = this.props;
+    dispatch(fetchTrendingStatuses());
+  }
+
+  render () {
+    const { isLoading, statusIds, multiColumn } = this.props;
+
+    const emptyMessage = <FormattedMessage id='empty_column.explore_statuses' defaultMessage='Nothing is trending right now. Check back later!' />;
+
+    return (
+      <StatusList
+        trackScroll
+        statusIds={statusIds}
+        scrollKey='explore-statuses'
+        hasMore={false}
+        isLoading={isLoading}
+        emptyMessage={emptyMessage}
+        bindToDocument={!multiColumn}
+        withCounters
+      />
+    );
+  }
+
+}