Fix event package display and add missing translations

- Correct Event->eventPackage relationship to HasOne
- Add missing translations for event packages and table columns

resources/lang/de/admin.php

@@ -371,6 +371,12 @@ return [
             'join' => 'Beitreten',
             'join_tokens_total' => 'Einladungen: :count',
             'join_tokens_missing' => 'Noch keine Einladungen erstellt',
+            'package' => 'Paket',
+        ],
+        'relation_managers' => [
+            'event_packages' => [
+                'title' => 'Event-Pakete',
+            ],
         ],
         'actions' => [
             'toggle_active' => 'Aktiv umschalten',