fix OOIION-1031 and advance OOIION-1030

- fix https://jira.oceanobservatories.org/tasks/browse/OOIION-1031

- partial https://jira.oceanobservatories.org/tasks/browse/OOIION-1030

All unit and integration tests passing.

Note: new PlatformAgentStreamPublisher to refactor related functionality in separate module and to facilitate alignment with AgentStreamPublisher later on.