private function createConfigurationFile($filename)
    {
        $absFilename = GeneralUtility::getFileAbsFileName($filename);
        if (file_exists($absFilename)) {
            // Add Flashmessage that there is already an configuration file and we are not going to override this.
            $flashMessage = GeneralUtility::makeInstance(
                FlashMessage::class,
                'There is already an ' . $filename . ' configuration file in the root directory, '
                . 'please make sure that configuration files are protected and the url rewritings are set properly. '
                . 'An example configuration is located at: "typo3conf/ext/bootstrap_package/Configuration/Server/_' . $filename . '"',
                'Webserver configuration file "' . $filename . '" already exists',
                FlashMessage::NOTICE,
                true
            );
            $this->addFlashMessage($flashMessage);
            return;
        }

        $filecontent = GeneralUtility::getUrl(ExtensionManagementUtility::extPath(self::EXT_KEY) . '/Configuration/Server/_' . $filename);
        if ($filecontent && is_string($filecontent)) {
            GeneralUtility::writeFile($absFilename, $filecontent, true);
            // Add Flashmessage that the example configuration file was placed in the root directory
            $flashMessage = GeneralUtility::makeInstance(
                FlashMessage::class,
                'For securing configuration files and optimization purposes an example ' . $filename . ' file was placed in your root directory.',
                'Webserver configuration file "' . $filename . '" was placed in the root directory.',
                FlashMessage::OK,
                true
            );
            $this->addFlashMessage($flashMessage);
        }
    }