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/FlashImmunityComponent.cs

@@ -0,0 +1,17 @@
+using Robust.Shared.Analyzers;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Server.Flash.Components
+{
+    [RegisterComponent, Friend(typeof(FlashSystem))]
+    public class FlashImmunityComponent : Component
+    {
+        public override string Name => "FlashImmunity";
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        [DataField("enabled")]
+        public bool Enabled { get; set; } = true;
+    }
+}