Supports the Delete NS Subscription operation and workflows which do the following sequence:

<Delete NS Subscription: note: the following workflow is a template, and it can be enhanced as needed.>

• Supports SOL005-compliant Delete NS Subscription operation
• Supports input parameters handling:
  • Initialize Parameters: set subscriptonId
• Deletes NFVO_SUBSCRIPTION DB for the subscriptionId
• if success, return 204 No Content
• else, return error