Adds access management to router and updates endpoints accordingly

lib/Router/Endpoints/Subscription.php

@@ -1,6 +1,8 @@
 <?php
+
 namespace MailPoet\Router\Endpoints;
 
+use MailPoet\Config\AccessControl;
 use MailPoet\Subscription as UserSubscription;
 
 if(!defined('ABSPATH')) exit;
@@ -16,6 +18,9 @@ class Subscription {
     self::ACTION_UNSUBSCRIBE
   );
   public $data;
+  public $permissions = array(
+    'global' => AccessControl::NO_ACCESS_RESTRICTION
+  );
 
   function __construct($data) {
     $this->data = $data;