chore: remove deprecated horses, clubs, officials, and persons services

- Deleted obsolete modules related to horses, clubs, officials, and persons services, including their configurations, build files, and database provisioning scripts.
- Cleaned up associated references in the project structure (e.g., `settings.gradle.kts`).
- Removed unused database tables and Spring beans related to these domains.

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

backend/services/masterdata/masterdata-domain/build.gradle.kts

@@ -1,6 +1,6 @@
 plugins {
-    alias(libs.plugins.kotlin.multiplatform)
-    alias(libs.plugins.kotlin.serialization)
+  alias(libs.plugins.kotlinMultiplatform)
+  alias(libs.plugins.kotlinSerialization)
 }
 
 kotlin {
@@ -20,6 +20,10 @@ kotlin {
         val commonTest by getting {
             dependencies {
                 implementation(kotlin("test"))
+            }
+        }
+      val jvmTest by getting {
+        dependencies {
                 implementation(projects.platform.platformTesting)
             }
         }