refactor provider interfaces

.gitlab/merge_request_templates/default.md

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

...opengroup/osdu/notification/auth/AuthorizationFilter.java

...oup/osdu/notification/auth/EntitlementsClientFactory.java

...group/osdu/notification/di/CredentialHeadersProvider.java

...group/osdu/notification/di/SubscriptionClientFactory.java

...osdu/notification/provider/interfaces/IAppProperties.java

...tification/provider/interfaces/IGoogleServiceAccount.java

...ication/provider/interfaces/IServiceAccountValidator.java

...org/opengroup/osdu/notification/utils/IAppProperties.java

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

...group/osdu/notification/auth/AuthorizationFilterTest.java

...a/org/opengroup/osdu/notification/di/RequestInfoTest.java

.../osdu/notification/provider/azure/util/AppProperties.java

...provider/azure/util/AzureServiceAccountValidatorImpl.java

...ication/provider/azure/util/GoogleServiceAccountImpl.java

...up/osdu/notification/provider/gcp/util/AppProperties.java

...ification/provider/gcp/util/GoogleServiceAccountImpl.java

.../provider/gcp/util/GoogleServiceAccountValidatorImpl.java