Specs on how notifications shall be handled

Build a specification defining the notification we must handle and the way we will handle them. Propose to handle notifications associated with services (including all information associated with the service grouping) according to OpenROADM APIs. Notifications associated with alarms, state change, path computation result used in the scope of MDONs, and OFC demonstrations will be handled through Kafka broker and DMaaP. The scope of this task is to define a specification so that coders understands how to handle nbi-notification refactoring (TRNSPRTPCE-519) as well as OpenROADM service-notification ((TRNSPRTPCE-378)