chore: update module dependencies and remove unused imports

- Added `backend.infrastructure.persistence` to `@SpringBootApplication` scanBasePackages in `IdentityServiceApplication` and included it as a dependency in `build.gradle.kts`.
- Cleaned up unused imports in several files, including `Screens.kt`, `VeranstaltungScreens.kt`, and `TurnierAbrechnungTab.kt`.
- Updated `PingJpaEntity` to include `@Column` annotation for `createdAt` field.
- Refactored import ordering in `ZnsImportServiceTest` and `DatabaseFactory`.

Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>

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

@@ -15,6 +15,8 @@ dependencies {
   implementation(projects.core.coreUtils)
   implementation(projects.backend.services.identity.identityDomain)
   implementation(projects.backend.services.identity.identityInfrastructure)
+  implementation(projects.backend.infrastructure.security)
+  implementation(projects.backend.infrastructure.persistence)
 
   implementation(libs.spring.boot.starter.web)
   implementation(libs.spring.boot.starter.validation)