Added IExecutable and ISlotContainer interface.

Changed SlotContainerNode to ExecutableNode

Runtime/Models/Nodes/PropertyInput.cs

@@ -0,0 +1,28 @@
+using System;
+using UnityEngine;
+
+namespace Misaki.GraphView
+{
+    public class PropertyInput : ExecutableNode
+    {
+        [SerializeReference]
+        private ExposedProperty _property;
+        
+        public ExposedProperty Property => _property;
+        
+        [NodeOutput]
+        public object value;
+
+        public PropertyInput(ExposedProperty property)
+        {
+            _property = property;
+        }
+        
+        protected override bool OnExecute()
+        {
+            value = _property.Value;
+            
+            return true;
+        }
+    }
+}