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- Deleted outdated `ApplicationConfiguration` and `HorseRepositoryImpl` classes.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>

backend/services/horses/horses-infrastructure/build.gradle.kts

@@ -1,26 +1,26 @@
 plugins {
-    // KORREKTUR: Alle Plugins werden jetzt konsistent über den Version Catalog geladen.
-    alias(libs.plugins.kotlin.jvm)
-    alias(libs.plugins.kotlin.spring)
-    // Das JPA-Plugin wird jetzt ebenfalls zentral verwaltet.
-    alias(libs.plugins.kotlin.jpa)
+  alias(libs.plugins.kotlinJvm)
+  alias(libs.plugins.kotlinSpring)
+  alias(libs.plugins.kotlinSerialization)
 }
 
 dependencies {
     // Interne Module
     implementation(projects.platform.platformDependencies)
     implementation(projects.horses.horsesDomain)
-    implementation(projects.horses.horsesApplication)
+  // horses-common: ON HOLD
+  // implementation(projects.horses.horsesCommon)
     implementation(projects.core.coreDomain)
     implementation(projects.core.coreUtils)
-    implementation(projects.infrastructure.cache.cacheApi)
-    implementation(projects.infrastructure.eventStore.eventStoreApi)
-    implementation(projects.infrastructure.messaging.messagingClient)
 
-    // KORREKTUR: Alle externen Abhängigkeiten werden jetzt über den Version Catalog bezogen.
+  // Spring
+  implementation(libs.spring.boot.starter.web)
 
-    // Spring Data JPA
-    implementation(libs.spring.boot.starter.data.jpa)
+  // Datenbank via Exposed
+  implementation(libs.exposed.core)
+  implementation(libs.exposed.dao)
+  implementation(libs.exposed.jdbc)
+  implementation(libs.exposed.kotlin.datetime)
 
     // Datenbank-Treiber
     runtimeOnly(libs.postgresql.driver)