Move and rename damage effect to color flash effect (#18263)

* move damage effect to different package

* rename to ColorFlashEffect

* renaming some other things

Content.Shared/Weapons/DamageEffectComponent.cs

@@ -1,11 +0,0 @@
-namespace Content.Shared.Weapons;
-
-/// <summary>
-/// Stores the original sprite color for a damaged entity to be able to restore it later.
-/// </summary>
-[RegisterComponent]
-public sealed class DamageEffectComponent : Component
-{
-    [ViewVariables]
-    public Color Color = Color.White;
-}

Content.Shared/Weapons/Melee/DamageEffectEvent.cs

@@ -1,23 +0,0 @@
-using Robust.Shared.Serialization;
-
-namespace Content.Shared.Weapons.Melee;
-
-/// <summary>
-/// Raised on the server and sent to a client to play the damage animation.
-/// </summary>
-[Serializable, NetSerializable]
-public sealed class DamageEffectEvent : EntityEventArgs
-{
-    /// <summary>
-    /// Color to play for the damage flash.
-    /// </summary>
-    public Color Color;
-
-    public List<EntityUid> Entities;
-
-    public DamageEffectEvent(Color color, List<EntityUid> entities)
-    {
-        Color = color;
-        Entities = entities;
-    }
-}