feat(horses-service): remove legacy configuration and repository classes

- Deleted outdated `ApplicationConfiguration` and `HorseRepositoryImpl` classes.
- Migrated to streamlined modular Gradle configuration in `build.gradle.kts`.
- Updated domain models and dependencies to use multiplatform and serialization plugins.
- Added modular setup for `horses` namespace in `settings.gradle.kts`.
- Reorganized database configuration with minimal JDBC bindings for development.

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

core/core-domain/src/commonMain/kotlin/at/mocode/core/domain/model/Enums.kt

@@ -65,6 +65,17 @@ enum class VerifikationsStatusE {
   KORREKTUR_ERFORDERLICH
 }
 
+/**
+ * Geschlecht eines Pferdes gemäß ÖTO/ZNS-Klassifikation.
+ */
+@Serializable
+enum class PferdeGeschlechtE {
+  HENGST,
+  STUTE,
+  WALLACH,
+  UNBEKANNT
+}
+
 /**
  * Processing states for workflows and tasks.
  */