Merge branch 'users/nikhil/NotifServiceRedesign' into 'master'

NOTICE

...a/org/opengroup/osdu/notification/api/PubsubEndpoint.java

...in/java/org/opengroup/osdu/notification/auth/GsaAuth.java

...n/java/org/opengroup/osdu/notification/auth/HmacAuth.java

...opengroup/osdu/notification/auth/factory/AuthFactory.java

...engroup/osdu/notification/auth/interfaces/SecretAuth.java

...ngroup/osdu/notification/service/NotificationHandler.java

...ngroup/osdu/notification/service/SubscriptionHandler.java

.../opengroup/osdu/notification/api/PubsubEndpointTests.java

...ava/org/opengroup/osdu/notification/auth/GsaAuthTest.java

...va/org/opengroup/osdu/notification/auth/HmacAuthTest.java

...p/osdu/notification/service/NotificationHandlerTests.java

...p/osdu/notification/service/SubscriptionHandlerTests.java