Create system for handling serial connection to Jetson

[AG6GR]

Robotcode must receive the output of the CV pipeline running on the Jetson. This is done via a serial UART connection. On the CV side, the output of the pipeline must be converted into a string message. This message is then sent to the roboRIO, and parsed by a FSMSystem in robotcode.

This task entails:

• Defining the message format
• Writing a simple converter in Python to pack the CV output into the message
• Write robotcode FSMSystem that unpacks the CV output and provides API for other systems to use it

One tricky aspect of this task is that since the Jetson and RoboRIO aren't synchronized, the robotcode may not get a complete message every time it reads from the Serial port. So there's some interesting string handling to be done.