Added get/setPickupDelay on Item entities, thanks robin0van0der0v

By: Dinnerbone <dinnerbone@dinnerbone.com>

paper-api/src/main/java/org/bukkit/entity/Item.java

@@ -23,4 +23,18 @@ public interface Item extends Entity {
      * @param stack An item stack.
      */
     public void setItemStack(ItemStack stack);
+
+    /**
+     * Gets the delay before this Item is available to be picked up by players
+     *
+     * @return Remaining delay
+     */
+    public int getPickupDelay();
+
+    /**
+     * Sets the delay before this Item is available to be picked up by players
+     *
+     * @param delay New delay
+     */
+    public void setPickupDelay(int delay);
 }