When importing a xml-file, and not specifying a parent, the module gives a PHP
error.
It should in this case, import the given xml-file into the root level of the
site.

Or in worst-case give a error, that a parent must be specified.

PHP Fatal error:  Uncaught TypeError: Argument 2 passed to
CGContentUtils\\contentImporter::import() must be of the type integer, null
given, called in action.admin_import_content.php on line 25