SPIGOT-840, SPIGOT-2522: [Draft] Add EntityPotionEffectChangeEvent

Discussion ongoing in PR #449

By: kaenganxt <kaenganxt@mc-anura.de>

paper-server/nms-patches/ItemFood.patch

@@ -0,0 +1,11 @@
+--- a/net/minecraft/server/ItemFood.java
++++ b/net/minecraft/server/ItemFood.java
+@@ -36,7 +36,7 @@
+ 
+     protected void a(ItemStack itemstack, World world, EntityHuman entityhuman) {
+         if (!world.isClientSide && this.l != null && world.random.nextFloat() < this.m) {
+-            entityhuman.addEffect(new MobEffect(this.l));
++            entityhuman.addEffect(new MobEffect(this.l), org.bukkit.event.entity.EntityPotionEffectEvent.Cause.FOOD); // CraftBukkit
+         }
+ 
+     }