Added webpack.ProvidePlugin for most used imports

Removed imports of React, connect, PropTypes throughout
Removed the "React" in React.Component/PureComponent

app/javascript/gabsocial/containers/intersection_observer_article_container.js

@@ -1,4 +1,3 @@
-import { connect } from 'react-redux';
 import IntersectionObserverArticle from '../components/intersection_observer_article';
 import { setHeight } from '../actions/height_cache';