Adapt IDE helper to new autoloading mechanism

This is a new major version as the autoloading mechanism has changed and the files, which are taken to generate the IDE helper file are at a different place now.
Also the old ox* classes have been removed and only a mapping file was left, so these ox* classes were included into the IDE helper file.

Caveat:
The recommended way to use the global factory function oxNew is using the ::class notation and the virtual namespace:
$article = oxNew(\OxidEsales\Eshop\Application\Model\Article::class);
Autocompletion of methods on the $article variable does not work using this notation.