feat: Add online clients tracking and display on dashboard and server views

migrations/055_dashboard_online_now_translation.sql

@@ -0,0 +1,9 @@
+-- Add translation for dashboard.online_now
+INSERT INTO translations (`locale`, `category`, `key_name`, `translation`) VALUES
+('en', 'dashboard', 'online_now', 'Online Now'),
+('ru', 'dashboard', 'online_now', 'Сейчас онлайн'),
+('es', 'dashboard', 'online_now', 'En línea ahora'),
+('de', 'dashboard', 'online_now', 'Jetzt online'),
+('fr', 'dashboard', 'online_now', 'En ligne maintenant'),
+('zh', 'dashboard', 'online_now', '当前在线')
+ON DUPLICATE KEY UPDATE `translation` = VALUES(`translation`);