Consumables refactor (#1796)

* Removed broken EntityEatEvents - these don't fit the pattern since they only apply to Human entities anyway. PlayerItemConsumeEvent and PlayerInteractEvent can be used for cancellation purposes, and plugins can do custom stuff without mess.

* Restrict item consuming to Living entities only

* Added FoodSource->requiresHunger()

* Only items implementing the Consumable interface can now be consumed.

* The effects from consuming items are now generic-ized by way of the Living->consume() function. This is overridden in Human to allow applying food and hunger.

* Fixed the hardcoded mess for buckets

src/pocketmine/item/Consumable.php

@@ -23,14 +23,32 @@ declare(strict_types=1);
 
 namespace pocketmine\item;
 
+use pocketmine\block\Block;
 use pocketmine\entity\Effect;
+use pocketmine\entity\Living;
 
+/**
+ * Interface implemented by objects that can be consumed by mobs.
+ */
 interface Consumable{
 
+	/**
+	 * Returns the leftover that this Consumable produces when it is consumed. For Items, this is usually air, but could
+	 * be an Item to add to a Player's inventory afterwards (such as a bowl).
+	 *
+	 * @return Item|Block|mixed
+	 */
 	public function getResidue();
 
 	/**
 	 * @return Effect[]
 	 */
 	public function getAdditionalEffects() : array;
+
+	/**
+	 * Called when this Consumable is consumed by mob, after standard resulting effects have been applied.
+	 *
+	 * @param Living $consumer
+	 */
+	public function onConsume(Living $consumer);
 }