ability to subscribe events before add/remove auth item children

[padlyuck]

For example in config we can subscribe this events and create migrations in rbacHandler function automatically. This is usefull when you need automatically transfer user rights from dev to production server.

$config =  [
    'modules' => [
        'user-management' => [
            'on beforeAction' => function () use ($saveHandler) {
                \yii\base\Event::on(
                    \webvimark\modules\UserManagement\models\rbacDB\AbstractItem::className(),
                    \webvimark\modules\UserManagement\models\rbacDB\AbstractItem::EVENT_BEFORE_ADD_CHILDREN,
                    $rbacHandler
                );
                \yii\base\Event::on(
                    \webvimark\modules\UserManagement\models\rbacDB\AbstractItem::className(),
                    \webvimark\modules\UserManagement\models\rbacDB\AbstractItem::EVENT_BEFORE_REMOVE_CHILDREN,
                    $rbacHandler
                );
            }
        ]
    ]
];

[webvimark]

Nice! Thank you :)