Adds support for unlimited stacks (#5084)

Co-authored-by: ike709 <ike709@github.com>

Content.Server/Stack/StackSystem.cs

@@ -62,6 +62,8 @@ namespace Content.Server.Stack
             {
                 // Set the split stack's count.
                 SetCount(entity.Uid, amount, stackComp);
+                // Don't let people dupe unlimited stacks
+                stackComp.Unlimited = false;
             }
 
             return entity;

Content.Shared/Stacks/SharedStackComponent.cs

@@ -15,6 +15,7 @@ namespace Content.Shared.Stacks
     {
         public sealed override string Name => "Stack";
 
+
         [ViewVariables(VVAccess.ReadWrite)]
         [DataField("stackType", required:true, customTypeSerializer:typeof(PrototypeIdSerializer<StackPrototype>))]
         public string StackTypeId { get; private set; } = string.Empty;
@@ -34,6 +35,13 @@ namespace Content.Shared.Stacks
         [DataField("max")]
         public int MaxCount  { get; set; } = 30;
 
+        /// <summary>
+        ///     Set to true to not reduce the count when used.
+        /// </summary>
+        [DataField("unlimited")]
+        [ViewVariables(VVAccess.ReadOnly)]
+        public bool Unlimited { get; set; }
+
         [ViewVariables]
         public int AvailableSpace => MaxCount - Count;
     }

Content.Shared/Stacks/SharedStackSystem.cs

@@ -73,7 +73,11 @@ namespace Content.Shared.Stacks
             }
 
             // We do have enough things in the stack, so remove them and change.
+            if (!stack.Unlimited)
+            {
                 SetCount(uid, stack.Count - amount, stack);
+            }
+
             return true;
         }