Improve entity hierarchy by adding Mob interface.

By: md_5 <git@md-5.net>

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

@@ -0,0 +1,24 @@
+package org.bukkit.entity;
+
+/**
+ * Represents a Mob. Mobs are living entities with simple AI.
+ */
+public interface Mob extends LivingEntity {
+
+    /**
+     * Instructs this Mob to set the specified LivingEntity as its target.
+     * <p>
+     * Hostile creatures may attack their target, and friendly creatures may
+     * follow their target.
+     *
+     * @param target New LivingEntity to target, or null to clear the target
+     */
+    public void setTarget(LivingEntity target);
+
+    /**
+     * Gets the current target of this Mob
+     *
+     * @return Current target of this creature, or null if none exists
+     */
+    public LivingEntity getTarget();
+}