Actions System + UI (#2710)

Co-authored-by: Vera Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>

Content.Client/GameObjects/Components/HUD/Inventory/HumanInventoryInterfaceController.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using Content.Client.UserInterface;
 using Content.Client.Utility;
 using JetBrains.Annotations;
@@ -84,6 +85,16 @@ namespace Content.Client.GameObjects.Components.HUD.Inventory
         public override SS14Window Window => _window;
         private HumanInventoryWindow _window;
 
+        public override IEnumerable<ItemSlotButton> GetItemSlotButtons(Slots slot)
+        {
+            if (!_inventoryButtons.TryGetValue(slot, out var buttons))
+            {
+                return Enumerable.Empty<ItemSlotButton>();
+            }
+
+            return buttons;
+        }
+
         public override void AddToSlot(Slots slot, IEntity entity)
         {
             base.AddToSlot(slot, entity);