Notification views feedback implementation

[Fancien]

• Avoiding an issue where having the notification app disabled would create a lot of error messages in the JS console
• Enabling the notification app by default
• Showing the number of non-dismissed notifications in the navbar even on the notifications page
• Changing the column names in the Notification tables
• Changing the Dismiss buttons display in the Notification tables
• Moving the accordion collapsing system inside the NotificationCard component
• Adding an indicator in the card headers to show that the header is clickable
• Moving the card header number badge closer to the card title and changing its color to red
• Replacing the links to show/hide dismissed notifications by a switch toggler and linking react state to it
• Keeping the checked status of the switch when changing the user filter (in the admin view of notifications)

[Fancien]

Small issue with the Show dismissed switch that needs working on. The rest should be fine for review

EDIT: This is corrected now

[nirmeen]

@Fancien All works smoothly, great job. One thing to add is, admin notifications in navbar should be accessible only to data Stewards.