add IApiHandlerInitializer

Pilz.Net/Api/ApiServer.cs

@@ -160,6 +160,10 @@ public class ApiServer : IApiServer
 
     public virtual void RegisterHandler<T>(T instance) where T : class
     {
+        // Initialize
+        if (instance is IApiHandlerInitializer initializer)
+            initializer.Initialize(this);
+
         // Get all public instance methods
         var methods = typeof(T).GetMethods(BindingFlags.Instance | BindingFlags.Public);