[OTJ] Implementing "spree" mechanic (#12018)

* [OTJ] Implement Unfortunate Accident

* fix errors

* a few more things

* [OTJ] Implement Three Steps Ahead

* [OTJ] Implement Caught in the Crossfire

* [OTJ] Implement Insatiable Avarice

* add test

* [OTJ] Implement Explosive Derailment

* [OTJ] Implement Requisition Raid

* [OTJ] Implement Rustler Rampage

* add comment to test

* [OTJ] Implement Metamorphic Blast

* [OTJ] Implement Final Showdown

* rework cost addition, add test

* move cost application to its own loop

Mage/src/main/java/mage/abilities/Ability.java

@@ -514,6 +514,14 @@ public interface Ability extends Controllable, Serializable {
      */
     Ability withFirstModeFlavorWord(String flavorWord);
 
+    /**
+     * Sets cost word for first mode
+     *
+     * @param cost
+     * @return
+     */
+    Ability withFirstModeCost(Cost cost);
+
     /**
      * Creates the message about the ability casting/triggering/activating to
      * post in the game log before the ability resolves.