Remove superfluous addManaCost method (#11288)

* no need to specify mana cost, just add cost

* handle all mana costs through addcost method only

* eliminate another constructor

* more constructor cleanup

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

@@ -155,14 +155,6 @@ public interface Ability extends Controllable, Serializable {
      */
     ManaCosts<ManaCost> getManaCostsToPay();
 
-    /**
-     * Adds a {@link ManaCost} to this ability that must be paid before this
-     * ability is activated.
-     *
-     * @param cost The {@link ManaCost} to add.
-     */
-    void addManaCost(ManaCost cost);
-
     void addManaCostsToPay(ManaCost manaCost);
 
     /**