Stack components are now entirely logicless.

- GetState is handled in SharedStackSystem
- Adds friend attributes to the stack components

Content.Server/Stack/StackComponent.cs

@@ -1,11 +1,12 @@
 using Content.Shared.Stacks;
+using Robust.Shared.Analyzers;
 using Robust.Shared.GameObjects;
 using Robust.Shared.ViewVariables;
 
 namespace Content.Server.Stack
 {
     // TODO: Naming and presentation and such could use some improvement.
-    [RegisterComponent]
+    [RegisterComponent, Friend(typeof(StackSystem))]
     [ComponentReference(typeof(SharedStackComponent))]
     public class StackComponent : SharedStackComponent
     {