Supports SOL005-compliant Restful Northbound Subscription and Notification APIs for SO/SOL005 Adapter

• Supports the Subscription (POST ”/subscriptions”) API
• Supports sending the Notification to SOL005 Adapter by using the SO SOL005 Adapter client-provided interface);
  • POST notification based on the callbackUrl from the subscription) 

Note: secure communication is handled by a separate user story, SO-3165.