Move SleepingSystem to Shared & cleanup (#28672)

* Move SleepingSystem to Shared & cleanup

* Remove empty OnShutdown handler

Content.Shared/Bed/Sleep/SnoringComponent.cs

@@ -0,0 +1,12 @@
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Bed.Sleep;
+
+/// <summary>
+/// This is used for the snoring trait.
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+public sealed partial class SnoringComponent : Component
+{
+
+}