feat(train-sets): implement multi-locomotive support for train sets

- Added TrainSetLocomotive entity to link multiple locomotives to a train set.
- Updated TrainSet entity to include a OneToMany relationship with TrainSetLocomotive.
- Modified the train scheduling logic to require at least two locomotives for a train set.
- Enhanced the UI components to support selecting multiple locomotives.
- Introduced new permissions for viewing customs clearance.
- Updated migrations to create the train_set_locomotives table and backfill existing data.
- Implemented utility functions for managing train numbers based on cargo type and direction.
- Added tests for train number utilities to ensure correct functionality.

apps/edr-freight-api/src/modules/train-scheduling/train-scheduling.module.ts

@@ -7,6 +7,7 @@ import { LocomotivesModule } from '../locomotives/locomotives.module';
 import { RuleEngineModule } from '../rule-engine/rule-engine.module';
 import { Locomotive } from '../locomotives/entities/locomotive.entity';
 import { Route } from '../routes/entities/route.entity';
+import { TrainSetLocomotive } from '../train-sets/entities/train-set-locomotive.entity';
 import { TrainSetWagon } from '../train-sets/entities/train-set-wagon.entity';
 import { TrainSet } from '../train-sets/entities/train-set.entity';
 import { TrainSetsModule } from '../train-sets/train-sets.module';
@@ -30,6 +31,7 @@ import { NotificationsModule } from '../notifications/notifications.module';
       WagonType,
       TrainSet,
       TrainSetWagon,
+      TrainSetLocomotive,
       Route,
       Wagon,
       Container,