chore: create empty event

Author: andrea-acampora

src/main/kotlin/entities/events/EmptyEvent.kt

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2023. Smart Operating Block
+ *
+ * Use of this source code is governed by an MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT.
+ */
+
+package entities.events
+
+/**
+ * The event sent when the input has not to be propagated to the microservices.
+ */
+data class EmptyEvent(override val key: String = "EMPTY_EVENT", override val data: Any = "EMPTY_DATA" ) : Event<Any>