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>

gradle/libs.versions.toml

@@ -51,7 +51,7 @@ springdoc = "3.0.0"
 
 # Server Persistence
 # Final release 1.0.0 (UUID API refinements vs. rc-4)
-exposed = "1.0.0"
+exposed = "1.1.1"
 postgresql = "42.7.8"
 hikari = "7.0.2"
 h2 = "2.4.240"
@@ -100,6 +100,7 @@ benManesVersions = "0.51.0"
 detekt = "1.23.6"
 ktlint = "12.1.1"
 dokka = "2.1.0"
+firebaseDatabaseKtx = "22.0.1"
 
 [libraries]
 # ==============================================================================
@@ -280,6 +281,7 @@ archunit-junit5-engine = { module = "com.tngtech.archunit:archunit-junit5-engine
 kotlin-bom = { module = "org.jetbrains.kotlin:kotlin-bom", version.ref = "kotlin" }
 kotlinx-coroutines-bom = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-bom", version.ref = "kotlinx-coroutines" }
 kotlinx-coroutines-reactor = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-reactor", version.ref = "kotlinx-coroutines" }
+firebase-database-ktx = { group = "com.google.firebase", name = "firebase-database-ktx", version.ref = "firebaseDatabaseKtx" }
 
 [bundles]
 # === FRONTEND BUNDLES ===