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/generated_setting.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.
 
@@ -10,15 +12,15 @@ import {FormattedMessage} from 'react-intl';
 export default class GeneratedSetting extends React.Component {
     static get propTypes() {
         return {
-            id: React.PropTypes.string.isRequired,
-            label: React.PropTypes.node.isRequired,
-            placeholder: React.PropTypes.string,
-            value: React.PropTypes.string.isRequired,
-            onChange: React.PropTypes.func.isRequired,
-            disabled: React.PropTypes.bool.isRequired,
-            disabledText: React.PropTypes.node,
-            helpText: React.PropTypes.node.isRequired,
-            regenerateText: React.PropTypes.node
+            id: PropTypes.string.isRequired,
+            label: PropTypes.node.isRequired,
+            placeholder: PropTypes.string,
+            value: PropTypes.string.isRequired,
+            onChange: PropTypes.func.isRequired,
+            disabled: PropTypes.bool.isRequired,
+            disabledText: PropTypes.node,
+            helpText: PropTypes.node.isRequired,
+            regenerateText: PropTypes.node
         };
     }