Refactors flashes to ECS, sunglasses protect you from being flashed. (#4579)

* Refactors flashes to ECS, sunglasses protect you from being flashed.

* VV ReadWrite for FlashImmunity Enabled.

* Use cached IEntityLookup.

* Consistent formatting.

* Fix flashbang duration.
Flash duration is a mess.

* Small area flash code cleanup.

* Flashable state is only sent to attached player.

Content.Server/Flash/Components/FlashComponent.cs

@@ -1,11 +1,12 @@
 using Content.Shared.Sound;
+using Robust.Shared.Analyzers;
 using Robust.Shared.GameObjects;
 using Robust.Shared.Serialization.Manager.Attributes;
 using Robust.Shared.ViewVariables;
 
 namespace Content.Server.Flash.Components
 {
-    [RegisterComponent]
+    [RegisterComponent, Friend(typeof(FlashSystem))]
     public class FlashComponent : Component
     {
         public override string Name => "Flash";