Added webpack.ProvidePlugin for most used imports

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

app/javascript/gabsocial/features/ui/components/user_panel.js

@@ -1,6 +1,3 @@
-import React from 'react';
-import PropTypes from 'prop-types';
-import { connect } from 'react-redux';
 import { Link } from 'react-router-dom';
 import { injectIntl, FormattedMessage } from 'react-intl';
 import { autoPlayGif, me } from '../../../initial_state';