Interop Client: Publisher for other vehicle telemetry

[rland93]

We need, eventually, to have access to the telemetry produced by other vehicles.

• Write a publisher that publishes telemetry from other vehicles on the interop server
• Pay careful attention to the structure of the telemetry shared by the interop server. There is probably an existing ROS package (just like how we don't write our own geometry messages, we use nav_msgs or geometry_msgs instead) that is capable of handling whatever is produced

Probably, this is going to be asynchronous: start the publisher, then when new telem data is recieved, a callback publishes to the topic.