Add income update success message in DirectorInfo component

- Implemented a success message display for income updates in the DirectorInfo component, enhancing user feedback after successful updates.
- Added a timeout to automatically hide the success message after 3 seconds.
- Updated localization files to include new translations for income-related messages in both German and English, improving user experience for multilingual users.

frontend/src/i18n/locales/de/falukant.json

@@ -149,6 +149,8 @@
                 },
                 "name": "Name",
                 "salary": "Gehalt",
+                "income": "Einkommen",
+                "incomeUpdated": "Gehalt wurde erfolgreich aktualisiert.",
                 "satisfaction": "Zufriedenheit",
                 "fire": "Feuern",
                 "teach": "Weiterbilden",
@@ -838,6 +840,7 @@
                 "governor": "Gouverneur",
                 "super-state-administrator": "Oberstaatsverwalter",
                 "state-administrator": "Staatsverwalter",
+                "consultant": "Berater",
                 "ruler-consultant": "Berater des Herrschers",
                 "territorial-council-speaker": "Sprecher des Territorialrats",
                 "territorial-council": "Territorialrat",