ilCtrl: Add Exception for baseClass/cmdClass in Removing Slashes from $_GET

[fhelfer]

References https://github.com/ILIAS-eLearning/ILIAS/pull/7055/ Adding the possiblity to Use namepaces in Routing This will most likely not open us up to attacks from outside, because other characters will still be removed $this->ctrl->setCmdClass() will also check for correct Path and else default to baseClass or null

Best, @fhelfer