Updated frontend notification filtering and configuration

• Updated:
- frontend notification filtering and configuration

• Added:
- lastReadNotificationId to initial_state
- minWidth20PX for responsive notification icon hiding on xs

• Removed:
- unused code

app/javascript/styles/global.css

@@ -497,6 +497,7 @@ body {
 .maxWidth100PC42PX { max-width: calc(100% - 42px); }
 
 .minWidth330PX { min-width: 330px; }
+.minWidth20PX { min-width: 20px; }
 .minWidth14PX { min-width: 14px; }
 
 .width100PC { width: 100%; }