Added defualt graph properties inspector;

Added sticky note;

Changed the name of BaseNode to SlotContainerNode in case we need other type of nodes in the future;

Sample/Editor/View/SampleGraphAssetEditor.cs

@@ -0,0 +1,45 @@
+using Misaki.GraphView.Editor;
+using UnityEditor;
+using UnityEditor.Callbacks;
+using UnityEngine;
+using UnityEngine.UIElements;
+
+namespace Misaki.GraphView.Sample.Editor
+{
+    [CustomEditor(typeof(SampleGraphAsset))]
+    public class SampleGraphAssetEditor : GraphObjectEditor
+    {
+        [OnOpenAsset]
+        public static bool OnOpenAsset(int instanceID, int line)
+        {
+            var asset = EditorUtility.InstanceIDToObject(instanceID) as SampleGraphAsset;
+
+            if (asset != null)
+            {
+                SampleGraphEditor.Open(asset);
+                return true;
+            }
+
+            return false;
+        }
+
+        public override VisualElement CreateInspectorGUI()
+        {
+            var root = new VisualElement();
+            var graphProperties = CreateInspectorProperty();
+            
+            var executeButton = new Button(() =>
+            {
+                var graph = target as SampleGraphAsset;
+                graph?.Execute();
+            })
+            {
+                text = "Execute"
+            };
+            
+            root.Add(graphProperties);
+            root.Add(executeButton);
+            return root;
+        }
+    }
+}