refactor: revamp devtools page

This commit refactors the development tools page to make it look better. Additionally, it makes small adjustments in the notifications and corrects missing strings from the page.

app/Notifications/AbsenceRequestCancelled.php

@@ -49,7 +49,6 @@ class AbsenceRequestCancelled extends Notification implements ShouldQueue
                 ->subject(config('app.name').' - absence request cancelled')
                 ->line("This notification confirms that your recent Leave of Absence from {$this->absence->created_at} has just been cancelled by you.")
                 ->line('Please note that any inactivity will be counted in our activity metrics. You may also make a new request if you wish.')
-                ->action('View your request', url(route('absences.show', ['absence' => $this->absence->id])))
                 ->action('Send new request', url(route('absences.create')))
                 ->salutation('The team at ' . config('app.name'));
     }