Threaded PixhawkInstruction publishing from buttons

[benjaminwp18]

The robot needs more than a single PixhawkInstruction to change its motion. On the actual codebase, we publish PixhawkInstructions continuously because the controller publishes state messages continuously.

To get bootcamp solutions working on the robot, I had to change their publishing functions to publish multiple (5-10) messages, sleeping in between. Doing that on the GUI thread freezes cam streams (not good). Doing that in a separate thread with Python (stackoverflow; don't use thread.join) doesn't freeze anything, but doesn't match how we do it in prod (okay).

Either use that threaded solution or figure out a different one that allows for continuous publishing.