Remove IContainer and move some functions to the system (#4351)

Robust.Shared/Containers/SharedContainerSystem.Remove.cs

@@ -0,0 +1,26 @@
+using Robust.Shared.GameObjects;
+
+namespace Robust.Shared.Containers;
+
+public abstract partial class SharedContainerSystem
+{
+    /// <summary>
+    /// Checks if the entity can be removed from this container.
+    /// </summary>
+    /// <returns>True if the entity can be removed, false otherwise.</returns>
+    public bool CanRemove(EntityUid toRemove, BaseContainer container)
+    {
+        if (!container.Contains(toRemove))
+            return false;
+
+        //raise events
+        var removeAttemptEvent = new ContainerIsRemovingAttemptEvent(container, toRemove);
+        RaiseLocalEvent(container.Owner, removeAttemptEvent, true);
+        if (removeAttemptEvent.Cancelled)
+            return false;
+
+        var gettingRemovedAttemptEvent = new ContainerGettingRemovedAttemptEvent(container, toRemove);
+        RaiseLocalEvent(toRemove, gettingRemovedAttemptEvent, true);
+        return !gettingRemovedAttemptEvent.Cancelled;
+    }
+}