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

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

• Supports SOL005-compliant Get NS Subscription operation
• Supports input parameters handling:
  • Initializes Parameter: set subscription_id, params
• if there is no param, 
  • Queries NFVO_SUBSCRIPTION DB for all
  • Returns LccSubscription[]
• else if there is param, subscriptionId,
  • Queries NFVO_SUBSCRIPTION DB for the subscriptionId
  • Returns LccSubscription