Add shutdown hook

Signed-off-by: Graham <gpe@openrs2.org>

game/src/main/kotlin/org/openrs2/game/GameServer.kt

@@ -13,16 +13,28 @@ public class GameServer @Inject constructor(
     private val serviceManager = ServiceManager(services)
 
     public fun run(start: Long) {
-        serviceManager.startAsync().awaitHealthy()
+        val shutdownHook = Thread(::stop)
+
+        serviceManager.startAsync()
+        runtime.addShutdownHook(shutdownHook)
+        serviceManager.awaitHealthy()
 
         val elapsed = System.nanoTime() - start
         logger.info { "Started OpenRS2 in ${elapsed / NANOS_PER_MILLI} milliseconds" }
 
         serviceManager.awaitStopped()
+        runtime.removeShutdownHook(shutdownHook)
+    }
+
+    private fun stop() {
+        logger.info { "Stopping OpenRS2..." }
+        serviceManager.stopAsync().awaitStopped()
+        logger.info { "Stopped OpenRS2" }
     }
 
     private companion object {
         private val logger = InlineLogger()
+        private val runtime = Runtime.getRuntime()
         private const val NANOS_PER_MILLI = 1_000_000
     }
 }