Improvements in the validation process:

 - Files are generated directly in the build directory in any case
 - If enabled, files are also copied under /var/www/html/api/nfv/..
 - Both YAML and JSON versions are generated

Change-Id: I1f64926892a9476293d5224a8d9d78e238f25da6
Signed-off-by: Michele Carignani <michele.carignani@etsi.org>