PLT-2257 Reorganized System Console (#3003)

* Reorganized system console

* Fixed the names of some components

* Fixed timestamp for BrandImageSetting

* Fixed merge issues

* Updated push notification settings to match master branch

* Removed top level setting pages and moved enable Gitlab/LDAP settings onto their respective pages

* Re-added restrictDirectMessage setting to system console

* Re-added email connection test and fixed some margins

* Fixed ESLint errors

* Renamed Authentication > Onboarding to Authentication > Email in the system console

* Renamed Customization > Whitelabeling to Customization > Custom Branding in System Console

* Re-added EnableOpenServer to system console

webapp/components/admin_console/logs.jsx

@@ -99,4 +99,4 @@ export default class Logs extends React.Component {
             </div>
         );
     }
-}
+}