Refactor drag and drop to use a shared interface (#2012)

* WIP in progress hours

* Cleanup

* Fix bugle

* Fix nullable error

* Merge fixes

* Merge fixes

* Merge fixes

Content.Shared/GameObjects/Components/Storage/SharedStorableComponent.cs

@@ -0,0 +1,32 @@
+using System;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Storage
+{
+    public abstract class SharedStorableComponent : Component
+    {
+        public override string Name => "Storable";
+        public override uint? NetID => ContentNetIDs.STORABLE;
+
+        public virtual int Size { get; set; }
+
+        public override void ExposeData(ObjectSerializer serializer)
+        {
+            base.ExposeData(serializer);
+
+            serializer.DataField(this, s => s.Size, "size", 1);
+        }
+    }
+
+    [Serializable, NetSerializable]
+    public class StorableComponentState : ComponentState
+    {
+        public readonly int Size;
+
+        public StorableComponentState(int size) : base(ContentNetIDs.STORABLE)
+        {
+            Size = size;
+        }
+    }
+}