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/admin_console/setting.jsx

@@ -1,34 +1,34 @@
+import PropTypes from 'prop-types';
+
 // Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
 import React from 'react';
 
-export default class Setting extends React.Component {
-    render() {
-        return (
-            <div className='form-group'>
-                <label
-                    className='control-label col-sm-4'
-                    htmlFor={this.props.inputId}
-                >
-                    {this.props.label}
-                </label>
-                <div className='col-sm-8'>
-                    {this.props.children}
-                    <div className='help-text'>
-                        {this.props.helpText}
-                    </div>
+export default function Setting(props) {
+    return (
+        <div className='form-group'>
+            <label
+                className='control-label col-sm-4'
+                htmlFor={props.inputId}
+            >
+                {props.label}
+            </label>
+            <div className='col-sm-8'>
+                {props.children}
+                <div className='help-text'>
+                    {props.helpText}
                 </div>
             </div>
-        );
-    }
+        </div>
+    );
 }
 Setting.defaultProps = {
 };
 
 Setting.propTypes = {
-    inputId: React.PropTypes.string,
-    label: React.PropTypes.node.isRequired,
-    children: React.PropTypes.node.isRequired,
-    helpText: React.PropTypes.node
+    inputId: PropTypes.string,
+    label: PropTypes.node.isRequired,
+    children: PropTypes.node.isRequired,
+    helpText: PropTypes.node
 };