Improved notifications cleaning UI with set operations (#109)

* added notification cleaning drawer

* bugfix

* fully implemented set operations for notif cleaning

* i18n for notif cleaning drawer & improved logic slightly. Also added a confirm dialog

* - notif dismiss "overlay" now shoves the notif aside to avoid overlap
- added focus ring to header buttons
- removed notif overlay entirely from DOM if mode is disabled

* removed comment

* CSS tuning - inconsistent division lines fix

app/javascript/glitch/components/notification/container.js

@@ -45,6 +45,7 @@ const makeMapStateToProps = () => {
   const mapStateToProps = (state, props) => ({
     notification: getNotification(state, props.notification, props.accountId),
     settings: state.get('local_settings'),
+    notifCleaning: state.getIn(['notifications', 'cleaningMode']),
   });
 
   return mapStateToProps;