Add utility AI (#806)

Co-authored-by: Pieter-Jan Briers <pieterjan.briers@gmail.com>
Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>
Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Content.Server/AI/Operators/Inventory/UseItemInHandsOperator.cs

@@ -0,0 +1,49 @@
+using Content.Server.GameObjects;
+using Robust.Shared.Interfaces.GameObjects;
+
+namespace Content.Server.AI.Operators.Inventory
+{
+    /// <summary>
+    /// Will find the item in storage, put it in an active hand, then use it
+    /// </summary>
+    public class UseItemInHandsOperator : AiOperator
+    {
+        private readonly IEntity _owner;
+        private readonly IEntity _target;
+
+        public UseItemInHandsOperator(IEntity owner, IEntity target)
+        {
+            _owner = owner;
+            _target = target;
+        }
+
+        public override Outcome Execute(float frameTime)
+        {
+            if (_target == null)
+            {
+                return Outcome.Failed;
+            }
+
+            // TODO: Also have this check storage a la backpack etc.
+            if (!_owner.TryGetComponent(out HandsComponent handsComponent))
+            {
+                return Outcome.Failed;
+            }
+
+            if (_target.TryGetComponent(out ItemComponent itemComponent))
+            {
+                return Outcome.Failed;
+            }
+
+            foreach (var slot in handsComponent.ActivePriorityEnumerable())
+            {
+                if (handsComponent.GetHand(slot) != itemComponent) continue;
+                handsComponent.ActiveIndex = slot;
+                handsComponent.ActivateItem();
+                return Outcome.Success;
+            }
+
+            return Outcome.Failed;
+        }
+    }
+}