Added WIP for new News page Panels

• Added:
- WIP for new News page Panels: GabNewsPanel, LatestFromGabPanel, PopularLinks, TrendsFeedsPanel, TrendsHeadlinesPanel
- all imports for above in async_components

• Todo:
- Remove tests

app/javascript/gabsocial/components/panel/popular_links_panel.js

@@ -0,0 +1,79 @@
+import React from 'react'
+import PropTypes from 'prop-types'
+import { connect } from 'react-redux'
+import { fetchPopularLinks } from '../../actions/links'
+import ImmutablePureComponent from 'react-immutable-pure-component'
+import ImmutablePropTypes from 'react-immutable-proptypes'
+import PanelLayout from './panel_layout'
+import PreviewCardItem from '../preview_card_item'
+
+class PopularLinksPanel extends ImmutablePureComponent {
+
+  state = {
+    fetched: false,
+  }
+
+  static getDerivedStateFromProps(nextProps, prevState) {
+    if (nextProps.shouldLoad && !prevState.fetched) {
+      return { fetched: true }
+    }
+
+    return null
+  }
+
+  componentDidUpdate(prevProps, prevState) {
+    if (!prevState.fetched && this.state.fetched && this.props.isLazy) {
+      this.props.dispatch(fetchPopularLinks())
+    }
+  }
+
+  componentDidMount() {
+    if (!this.props.isLazy) {
+      this.props.dispatch(fetchPopularLinks())
+      this.setState({ fetched: true })
+    }
+  }
+
+  render() {
+    const {
+      intl,
+      popularLinksIsLoading,
+      popularLinksItems,
+    } = this.props
+    const { fetched } = this.state
+  
+    const count = !!popularLinksItems ? popularLinksItems.count() : 0
+    // : TESTING :
+    // if (count === 0 && fetched) return null
+
+    return (
+      <PanelLayout
+        title='Trending Links on Gab'
+        subtitle='Most popular links on Gab in last 15 minutes'
+      >
+        <div className={[_s.d, _s.w100PC].join(' ')}>
+          { /*
+            popularLinksItems.map((id, i) => (
+              <PreviewCardItem id={id} key={`preview-card-${id}-${i}`} />
+            ))
+            */ }
+            <PreviewCardItem id={'144'} />
+            <PreviewCardItem id={'144'} />
+            <PreviewCardItem id={'144'} />
+        </div>
+      </PanelLayout>
+    )
+  }
+}
+
+const mapStateToProps = (state) => ({
+  popularLinksIsLoading: state.getIn(['links', 'popular', 'isLoading']),
+  popularLinksItems: state.getIn(['links', 'popular', 'items']),
+})
+
+PopularLinksPanel.propTypes = {
+  popularLinksIsLoading: PropTypes.bool.isRequired,
+  popularLinksItems: ImmutablePropTypes.list.isRequired,
+}
+
+export default connect(mapStateToProps)(PopularLinksPanel)