PLT-7: Refactoring frontend (chunk 1)

- System console sidebar
- Sytem console email settings
- Error Bar
- Loading Screen
- Select Team Modal
- Add npm mm-intl package

web/react/components/loading_screen.jsx

@@ -1,6 +1,8 @@
 // Copyright (c) 2015 Mattermost, Inc. All Rights Reserved.
 // See License.txt for license information.
 
+import {FormattedMessage} from 'mm-intl';
+
 export default class LoadingScreen extends React.Component {
     constructor(props) {
         super(props);
@@ -13,7 +15,12 @@ export default class LoadingScreen extends React.Component {
                 style={{position: this.props.position}}
             >
                 <div className='loading__content'>
-                    <h3>Loading</h3>
+                    <h3>
+                        <FormattedMessage
+                            id='loading_screen.loading'
+                            defaultMessage='Loading'
+                        />
+                    </h3>
                     <div className='round round-1'></div>
                     <div className='round round-2'></div>
                     <div className='round round-3'></div>