Add Shutdown API to both Pool and JDS

[Shourya742]

We have shutdown APIs for both the translator and the JD client. To maintain consistency across the roles, we should take the same set of api's for the Pool and the JD server.

[jbesraa]

You dont need new issue for each role. #1320 is the general issue, it gives jdc and translator as examples, but it refers to all roles