public static ApplicationPackageXmlFilesValidator create(File appDir, Version vespaVersion) {
        return new ApplicationPackageXmlFilesValidator(new AppSubDirs(appDir), vespaVersion);
    }
Validation of xml files in application package against RELAX NG schemas.

@author hmusum
config-application-package/src/main/java/com/yahoo/config/model/application/provider/ApplicationPackageXmlFilesValidator.java