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/src/main/resources/db/control/V1__init_control_and_tenants.sql

@@ -7,7 +7,7 @@ CREATE TABLE IF NOT EXISTS control.tenants (
   db_url        TEXT NULL,
   status        TEXT NOT NULL DEFAULT 'ACTIVE', -- ACTIVE | READ_ONLY | LOCKED
   version       INT  NOT NULL DEFAULT 1,
-  created_at    TIMESTAMPTZ NOT NULL DEFAULT now()
+  created_at    TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now()
 );
 
 -- Index to speed up lookups by status when we add list operations later

backend/services/entries/entries-service/src/main/resources/db/tenant/V8__add_bewerb_financial_fields.sql

@@ -0,0 +1,3 @@
+-- Migration: Hinzufügen von Finanz-Feldern zu Bewerben für automatische Buchung
+ALTER TABLE bewerbe ADD COLUMN IF NOT EXISTS nenngeld_cent BIGINT;
+ALTER TABLE bewerbe ADD COLUMN IF NOT EXISTS nachnenngebuehr_cent BIGINT;