Introduced dialogue graph magic, created assest and importers. Added events for broadcasting puzzle steps

Assets/Editor/Dialogue/DialogueGraph.cs

@@ -0,0 +1,20 @@
+using System;
+using UnityEngine;
+using UnityEditor;
+using Unity.GraphToolkit.Editor;
+
+namespace Editor.Dialogue
+{
+    [Serializable]
+    [Graph(AssetExtension)]
+    public class DialogueGraph : Graph
+    {
+        public const string AssetExtension = "dialoguegraph";
+        
+        [MenuItem("Assets/Create/Dialogue Graph", false)]
+        private static void CreateAssetFile()
+        {
+            GraphDatabase.PromptInProjectBrowserToCreateNewAsset<DialogueGraph>();
+        }
+    }
+}