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-schedules/train-schedules.repository.ts

@@ -25,6 +25,7 @@ export class TrainSchedulesRepository extends BaseRepository<TrainSchedule> {
         route: true,
         trainSet: {
           locomotive: true,
+          locomotives: { locomotive: true },
           wagons: {
             wagonType: true,
             physicalWagon: true,