Deprecate IActionBlocker in favour of cancellable events (#4193)

* Deprecate IActionBlocker in favour of cancellable events

* Bring back old speech/emoting component restrictions

* Rename action blocker listener methods

* Use Entity System public methods instead of extension methods

Co-authored-by: Vera Aguilera Puerto <gradientvera@outlook.com>

Content.Shared/DragDrop/DropAttemptEvent.cs

@@ -0,0 +1,14 @@
+using Robust.Shared.GameObjects;
+
+namespace Content.Shared.DragDrop
+{
+    public class DropAttemptEvent : CancellableEntityEventArgs
+    {
+        public DropAttemptEvent(IEntity entity)
+        {
+            Entity = entity;
+        }
+
+        public IEntity Entity { get; }
+    }
+}