[services] Tunnelbroker - Adding tokio-stream dependency to the Cargo

Summary:
This diff adds the tokio-stream crate as a dependency.
We are using tokio_stream::wrappers in the following D5528 diff to wrap the streams and bind them to the tokio::sync::mpsc queue to iterate over it.

Linear task: ENG-2060

Test Plan: Service is successfully built in the following D5528 using this crate.

Reviewers: jon, marcin, varun, ashoat

Reviewed By: jon, ashoat

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5527