Rework emergency lights (#1830)

* Implement emergency lights reacting to lost power

* Add emergency light sprites
Remove shared emergency light component

* Remove unused import

* Remove EmergencyLight NetID

* Add rich description
Change comments
Add license
Implement ExposeData

Co-authored-by: Julian Giebel <j.giebel@netrocks.info>

Content.Server/GameObjects/EntitySystems/EmergencyLightSystem.cs

@@ -0,0 +1,18 @@
+using Content.Server.GameObjects.Components.Power.ApcNetComponents.PowerReceiverUsers;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects.Systems;
+
+namespace Content.Server.GameObjects.EntitySystems
+{
+    [UsedImplicitly]
+    internal sealed class EmergencyLightSystem : EntitySystem
+    {
+        public override void Update(float frameTime)
+        {
+            foreach (var comp in ComponentManager.EntityQuery<EmergencyLightComponent>())
+            {
+                comp.OnUpdate(frameTime);
+            }
+        }
+    }
+}