Consider reading robot-settings.toml files if no robot.py is present

[trickeydan]

Current behaviour: A robot-settings.toml will only be read if a robot.py is present. This is because students are assumed to be running code on their robot if they are accessing the web interface.

A student in Discord was confused that the robot-settings.toml was not detected when it was on a USB stick by itself. The student did not have any code to run, but wanted to access SSH.

We advised the student to add a robot.py to their USB.

I'm not sure if there's a real use case here, but it might reduce confusion as we encourage students to access the robot via SSH.

This may also have an impact if we decide to allow execution of code over the wifi interface.