ECS dragdrop (#12973)

* ECS dragdrop

No more excuses.

* AAAAAAAAAAAAAA

* kry

* events

* aaaaaaaaaa

* HUH

* Fix stripping

* aaaaaa

* spoike

* asease

* fix table vaulting

* ded

* rebiew

* aaaaaaaaaaaaa

* drag

* aeaeae

* weh

Content.Shared/Hands/HandEvents.cs

@@ -7,6 +7,14 @@ using static Robust.Shared.GameObjects.SharedSpriteComponent;
 
 namespace Content.Shared.Hands
 {
+    /// <summary>
+    /// Raised directed on an entity when attempting to drop its hand items.
+    /// </summary>
+    public sealed class DropAttemptEvent : CancellableEntityEventArgs
+    {
+        public readonly EntityUid Uid;
+    }
+
     /// <summary>
     ///     Raised directed at an item that needs to update its in-hand sprites/layers.
     /// </summary>