add bonus calendar api

api/src/main/java/eu/darkbot/api/managers/BonusCalendarAPI.java

@@ -0,0 +1,40 @@
+package eu.darkbot.api.managers;
+
+import eu.darkbot.api.API;
+
+import java.util.List;
+
+public interface BonusCalendarAPI extends API.Singleton {
+    /**
+     * @return number of days claimed
+     */
+    int getDaysClaimed();
+
+    /**
+     * @return The {@code List} of all rewards from rewards list
+     */
+    List<? extends Reward> getRewardList();
+
+    /**
+     * @return if reward is claimable for the day
+     */
+    boolean isClaimable();
+
+
+    /**
+     * In game rewards loot representation, includes loot id, &amp; amount
+     */
+    interface Reward {
+
+        /**
+         * @return in game variable name of reward
+         */
+        String getLootId();
+
+        /**
+         * @return amount of reward
+         */
+        int getAmount();
+
+    }
+}