Cult spells update (#607)

* - add: CultSystem.BloodSpells.

* - add: Cleanup.

Content.Shared/_White/Cult/UI/BloodSpellMessage.cs

@@ -0,0 +1,22 @@
+using Content.Shared.Eui;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared._White.Cult.UI;
+
+public enum BloodSpellMessageState : byte
+{
+    Create,
+    Remove,
+    Cancel
+}
+
+[Serializable, NetSerializable]
+public sealed class BloodSpellMessage : EuiMessageBase
+{
+    public readonly BloodSpellMessageState State;
+
+    public BloodSpellMessage(BloodSpellMessageState state)
+    {
+        State = state;
+    }
+}