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- Deleted outdated `ApplicationConfiguration` and `HorseRepositoryImpl` classes.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

settings.gradle.kts

@@ -73,6 +73,52 @@ include(":backend:services:entries:entries-api")
 // Code liegt im Branch: feature/entries-service
 // include(":backend:services:entries:entries-service")
 
+// --- HORSES (Pferde-Verwaltung) ---
+// Namespace ':horses:*' damit projects.horses.* Accessors funktionieren
+include(":horses")
+project(":horses").projectDir = file("backend/services/horses")
+include(":horses:horses-domain")
+// horses-common: ON HOLD – veraltete API-Referenzen
+// include(":horses:horses-common")
+include(":horses:horses-infrastructure")
+// horses-api: ON HOLD – Ktor-basiert, wird separat aktiviert
+// include(":horses:horses-api")
+include(":horses:horses-service")
+project(":horses:horses-domain").projectDir = file("backend/services/horses/horses-domain")
+// project(":horses:horses-common").projectDir = file("backend/services/horses/horses-common")
+project(":horses:horses-infrastructure").projectDir = file("backend/services/horses/horses-infrastructure")
+project(":horses:horses-service").projectDir = file("backend/services/horses/horses-service")
+
+// --- PERSONS (Personen/Reiter) ---
+include(":persons")
+project(":persons").projectDir = file("backend/services/persons")
+include(":persons:persons-domain")
+include(":persons:persons-infrastructure")
+include(":persons:persons-service")
+project(":persons:persons-domain").projectDir = file("backend/services/persons/persons-domain")
+project(":persons:persons-infrastructure").projectDir = file("backend/services/persons/persons-infrastructure")
+project(":persons:persons-service").projectDir = file("backend/services/persons/persons-service")
+
+// --- CLUBS (Vereine) ---
+include(":clubs")
+project(":clubs").projectDir = file("backend/services/clubs")
+include(":clubs:clubs-domain")
+include(":clubs:clubs-infrastructure")
+include(":clubs:clubs-service")
+project(":clubs:clubs-domain").projectDir = file("backend/services/clubs/clubs-domain")
+project(":clubs:clubs-infrastructure").projectDir = file("backend/services/clubs/clubs-infrastructure")
+project(":clubs:clubs-service").projectDir = file("backend/services/clubs/clubs-service")
+
+// --- OFFICIALS (Richter) ---
+include(":officials")
+project(":officials").projectDir = file("backend/services/officials")
+include(":officials:officials-domain")
+include(":officials:officials-infrastructure")
+include(":officials:officials-service")
+project(":officials:officials-domain").projectDir = file("backend/services/officials/officials-domain")
+project(":officials:officials-infrastructure").projectDir = file("backend/services/officials/officials-infrastructure")
+project(":officials:officials-service").projectDir = file("backend/services/officials/officials-service")
+
 // --- PING (Ping Service) ---
 include(":backend:services:ping:ping-service")