Updating client dependencies. Switching to yarn. (#6433)

* Updating client dependancies. Switching to using yarn.

* Updating React

* Moving pure components to using function syntax (performance gains with newer react version)

* Updating client dependancies.

* Ignore .yarninstall

* Enabling pre-lockfile because it's the entire point of using yarn.

* Removing old webpack config

* Moving to new prop-types

* Fixing ESLint Errors

* Updating jest snapshots.

* Cleaning up package.json

webapp/components/searchable_user_list/searchable_user_list.jsx

@@ -2,6 +2,7 @@
 // See License.txt for license information.
 
 import $ from 'jquery';
+import PropTypes from 'prop-types';
 import React from 'react';
 import ReactDOM from 'react-dom';
 import {FormattedMessage} from 'react-intl';
@@ -14,23 +15,23 @@ const NEXT_BUTTON_TIMEOUT = 500;
 
 export default class SearchableUserList extends React.Component {
     static propTypes = {
-        users: React.PropTypes.arrayOf(React.PropTypes.object),
-        usersPerPage: React.PropTypes.number,
-        total: React.PropTypes.number,
-        extraInfo: React.PropTypes.object,
-        nextPage: React.PropTypes.func.isRequired,
-        previousPage: React.PropTypes.func.isRequired,
-        search: React.PropTypes.func.isRequired,
-        actions: React.PropTypes.arrayOf(React.PropTypes.func),
-        actionProps: React.PropTypes.object,
-        actionUserProps: React.PropTypes.object,
-        focusOnMount: React.PropTypes.bool,
-        renderCount: React.PropTypes.func,
-        renderFilterRow: React.PropTypes.func,
+        users: PropTypes.arrayOf(PropTypes.object),
+        usersPerPage: PropTypes.number,
+        total: PropTypes.number,
+        extraInfo: PropTypes.object,
+        nextPage: PropTypes.func.isRequired,
+        previousPage: PropTypes.func.isRequired,
+        search: PropTypes.func.isRequired,
+        actions: PropTypes.arrayOf(PropTypes.func),
+        actionProps: PropTypes.object,
+        actionUserProps: PropTypes.object,
+        focusOnMount: PropTypes.bool,
+        renderCount: PropTypes.func,
+        renderFilterRow: PropTypes.func,
 
-        page: React.PropTypes.number.isRequired,
-        term: React.PropTypes.string.isRequired,
-        onTermChange: React.PropTypes.func.isRequired
+        page: PropTypes.number.isRequired,
+        term: PropTypes.string.isRequired,
+        onTermChange: PropTypes.func.isRequired
     };
 
     static defaultProps = {

webapp/components/searchable_user_list/searchable_user_list_container.jsx

@@ -1,3 +1,5 @@
+import PropTypes from 'prop-types';
+
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
@@ -7,16 +9,16 @@ import SearchableUserList from './searchable_user_list.jsx';
 
 export default class SearchableUserListContainer extends React.Component {
     static propTypes = {
-        users: React.PropTypes.arrayOf(React.PropTypes.object),
-        usersPerPage: React.PropTypes.number,
-        total: React.PropTypes.number,
-        extraInfo: React.PropTypes.object,
-        nextPage: React.PropTypes.func.isRequired,
-        search: React.PropTypes.func.isRequired,
-        actions: React.PropTypes.arrayOf(React.PropTypes.func),
-        actionProps: React.PropTypes.object,
-        actionUserProps: React.PropTypes.object,
-        focusOnMount: React.PropTypes.bool
+        users: PropTypes.arrayOf(PropTypes.object),
+        usersPerPage: PropTypes.number,
+        total: PropTypes.number,
+        extraInfo: PropTypes.object,
+        nextPage: PropTypes.func.isRequired,
+        search: PropTypes.func.isRequired,
+        actions: PropTypes.arrayOf(PropTypes.func),
+        actionProps: PropTypes.object,
+        actionUserProps: PropTypes.object,
+        focusOnMount: PropTypes.bool
     };
 
     constructor(props) {