feat: Move event runtime implementation into core

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

core/lib/Event/DeferredEventProcessorInterface.php

@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KTXC\Event;
+
+interface DeferredEventProcessorInterface
+{
+    public function beginExecution(string $executionId): void;
+
+    public function processDeferred(string $executionId): DeferredProcessingResult;
+
+    public function discardDeferred(string $executionId): void;
+}