SDC has differences between the csar we onboard and the csar we distribute.

we have onboarding csar which is imported to catlog->vf csar ->service csar, they have minor differences in their structure.

currently, SDC artifact support has some limitation:
1. it only supports below directories: Deployment, Informational and auto-generated <VFC TOSCA name> under Artifacts, all others will be automatically removed
2. the valid relative path must be Artifacts/sub1/sub2/xxx.file.

the user can NOT put arbitrary artifacts under the specified Artifacts dir, need such support.  

Also, other cloud technologies, e.g. k8s, ARM (Azure Resource Template) and HOT(heat) need such support too.