Add vehicle repair functionality in Falukant module

- Implemented a new repairVehicle method in FalukantService to handle vehicle repairs, including cost calculation and precondition checks.
- Updated FalukantController to expose the repairVehicle endpoint, allowing users to initiate repairs via the API.
- Enhanced FalukantRouter to include a new route for vehicle repairs.
- Modified BranchView component to add UI elements for repairing vehicles, including a dialog for repair confirmation and displaying repair details.
- Updated German localization files to include translations related to vehicle repair actions, improving user experience for German-speaking users.

backend/routers/falukantRouter.js

@@ -75,6 +75,7 @@ router.get('/products/prices-in-cities', falukantController.getProductPricesInCi
 router.get('/vehicles/types', falukantController.getVehicleTypes);
 router.post('/vehicles', falukantController.buyVehicles);
 router.get('/vehicles', falukantController.getVehicles);
+router.post('/vehicles/:vehicleId/repair', falukantController.repairVehicle);
 router.post('/transports', falukantController.createTransport);
 router.get('/transports/route', falukantController.getTransportRoute);
 router.get('/transports/branch/:branchId', falukantController.getBranchTransports);