Makes machine parts stackable, removes unused field in stack prototypes (#28434)

* Makes machine parts stacks, removes unused field in stack prototypes

* forgor

* Fix tests

* Fixes lathe construction. Yes. This sucks but there's no better way that doesnt involve refactoring machine parts completely

* detail

* a

Content.Shared/Stacks/StackPrototype.cs

@@ -4,7 +4,7 @@ using Robust.Shared.Utility;
 
 namespace Content.Shared.Stacks;
 
-[Prototype("stack")]
+[Prototype]
 public sealed partial class StackPrototype : IPrototype
 {
     [ViewVariables]
@@ -15,33 +15,26 @@ public sealed partial class StackPrototype : IPrototype
     ///     Human-readable name for this stack type e.g. "Steel"
     /// </summary>
     /// <remarks>This is a localization string ID.</remarks>
-    [DataField("name")]
+    [DataField]
     public string Name { get; private set; } = string.Empty;
 
     /// <summary>
     ///     An icon that will be used to represent this stack type.
     /// </summary>
-    [DataField("icon")]
+    [DataField]
     public SpriteSpecifier? Icon { get; private set; }
 
     /// <summary>
     ///     The entity id that will be spawned by default from this stack.
     /// </summary>
-    [DataField("spawn", required: true, customTypeSerializer:typeof(PrototypeIdSerializer<EntityPrototype>))]
-    public string Spawn { get; private set; } = string.Empty;
+    [DataField(required: true)]
+    public EntProtoId Spawn { get; private set; } = string.Empty;
 
     /// <summary>
     ///     The maximum amount of things that can be in a stack.
     ///     Can be overriden on <see cref="StackComponent"/>
     ///     if null, simply has unlimited max count.
     /// </summary>
-    [DataField("maxCount")]
+    [DataField]
     public int? MaxCount { get; private set; }
-
-    /// <summary>
-    /// The size of an individual unit of this stack.
-    /// </summary>
-    [DataField("itemSize")]
-    public int? ItemSize;
 }
-