Redesign the landing page, mount public timeline on it (#4122)

* Redesign the landing page, mount public timeline on it

* Adjust the standalone mounted component to the lacking of router

* Adjust auth layout pages to new design

* Fix tests

* Standalone public timeline polling every 5 seconds

* Remove now obsolete translations

* Add responsive design for new landing page

* Address reviews

* Add floating clouds behind frontpage form

* Use access token from public page when available

* Fix mentions and hashtags links, cursor on status content in standalone mode

* Add footer link to source code

* Fix errors on pages that don't embed the component, use classnames

* Fix tests

* Change anonymous autoPlayGif default to false

* When gif autoplay is disabled, hover to play

* Add option to hide the timeline preview

* Slightly improve alt layout

* Add elephant friend to new frontpage

* Display "back to mastodon" in place of "login" when logged in on frontpage

* Change polling time to 3s

app/javascript/mastodon/features/standalone/public_timeline/index.js

@@ -0,0 +1,76 @@
+import React from 'react';
+import { connect } from 'react-redux';
+import PropTypes from 'prop-types';
+import StatusListContainer from '../../ui/containers/status_list_container';
+import {
+  refreshPublicTimeline,
+  expandPublicTimeline,
+} from '../../../actions/timelines';
+import Column from '../../../components/column';
+import ColumnHeader from '../../../components/column_header';
+import { defineMessages, injectIntl } from 'react-intl';
+
+const messages = defineMessages({
+  title: { id: 'standalone.public_title', defaultMessage: 'A look inside...' },
+});
+
+@connect()
+@injectIntl
+export default class PublicTimeline extends React.PureComponent {
+
+  static propTypes = {
+    dispatch: PropTypes.func.isRequired,
+    intl: PropTypes.object.isRequired,
+  };
+
+  handleHeaderClick = () => {
+    this.column.scrollTop();
+  }
+
+  setRef = c => {
+    this.column = c;
+  }
+
+  componentDidMount () {
+    const { dispatch } = this.props;
+
+    dispatch(refreshPublicTimeline());
+
+    this.polling = setInterval(() => {
+      dispatch(refreshPublicTimeline());
+    }, 3000);
+  }
+
+  componentWillUnmount () {
+    if (typeof this.polling !== 'undefined') {
+      clearInterval(this.polling);
+      this.polling = null;
+    }
+  }
+
+  handleLoadMore = () => {
+    this.props.dispatch(expandPublicTimeline());
+  }
+
+  render () {
+    const { intl } = this.props;
+
+    return (
+      <Column ref={this.setRef}>
+        <ColumnHeader
+          icon='globe'
+          title={intl.formatMessage(messages.title)}
+          onClick={this.handleHeaderClick}
+        />
+
+        <StatusListContainer
+          timelineId='public'
+          loadMore={this.handleLoadMore}
+          scrollKey='standalone_public_timeline'
+          trackScroll={false}
+        />
+      </Column>
+    );
+  }
+
+}