Get original vendor package under the ONBOARDING_PACKAGE directory from SDC resource CSAR.

According to mails from Zu Qiang [zu.qiang@ericsson.com], the VNF resource csar of SDC includes the original vendor package only when onboarding VNF package based on SOL004v2.6.1 format. It should be under the directory: \Artifacts\Deployment\ONBOARDED_PACKAGE