ECS AsteroidRock and add a doafter to mining (#6120)

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Server/RandomAppearance/RandomAppearanceSystem.cs

@@ -0,0 +1,27 @@
+using Robust.Shared.GameObjects;
+using Robust.Shared.IoC;
+using Robust.Shared.Log;
+using Robust.Shared.Random;
+using Robust.Shared.Reflection;
+
+namespace Content.Server.RandomAppearance;
+
+public class RandomAppearanceSystem : EntitySystem
+{
+    [Dependency] private readonly IRobustRandom _random = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<RandomAppearanceComponent, ComponentInit>(OnComponentInit);
+    }
+
+    private void OnComponentInit(EntityUid uid, RandomAppearanceComponent component, ComponentInit args)
+    {
+        if (TryComp(uid, out AppearanceComponent? appearance) && component.EnumKey != null)
+        {
+            appearance.SetData(component.EnumKey, _random.Pick(component.SpriteStates));
+        }
+    }
+}