Add ROS2 CI and Black Formatting for Python Nodes

[amalnanavati]

Since this repository has a few ROS2 nodes and some Python code, we should add CI that ensures the ROS2 nodes all compile and that the Python code is formatted (I'd suggest using the black formatter.

This is not critical path, since the ROS2 nodes in this repository are only for testing the web app. But it is nice-to-have.

[amalnanavati]

Also, if/when ROS2 CI and black formatting becomes an explicit part of the checks that must pass before merging, we should add documentation on how to run black formatter locally and how the CI ROS tests locally.