feat(entries+billing): integrate automatic fee booking for entries with billing service

- **Entries-Service Updates:**
  - Implemented automatic booking of fees (entry fees and late fees) during entry submission using `TeilnehmerKontoService`.
  - Enhanced `Bewerb` entity with financial fields (`nenngeldCent`, `nachnenngebuehrCent`).
  - Added Flyway migration to update `bewerbe` table with new financial fields.
  - Updated `EntriesServiceApplication` to include billing package scanning for integration.

- **Billing-Service Enhancements:**
  - Adjusted `TeilnehmerKontoService` to support fetching accounts by event and person.
  - Improved database configuration to handle missing JDBC URLs during tests.

- **Tests:**
  - Added integration tests to validate fee booking logic for entries, including late fee scenarios.
  - Introduced H2 database setup for test isolation.

- **Misc:**
  - Updated tenant-aware transactions to support H2 and PostgreSQL dialects.
  - Adjusted log and error handling for robust integration between services.

backend/services/entries/entries-service/build.gradle.kts

@@ -15,6 +15,8 @@ dependencies {
   implementation(projects.platform.platformDependencies)
   implementation(projects.backend.services.entries.entriesApi)
   implementation(projects.backend.services.entries.entriesDomain)
+  implementation(projects.backend.services.billing.billingDomain)
+  implementation(projects.backend.services.billing.billingService)
   implementation(projects.core.coreUtils)
   implementation(projects.core.coreDomain)
   implementation(projects.backend.infrastructure.monitoring.monitoringClient)