Document the provided ultrasound sensor

[PeterJCLaw]

For SR2025 we've provided an ultrasound sensor in the kit. The docs should be updated to explain how to use it.

There is existing mention of the software side of this in the Arduino API, however that relies on knowing that the Arduino is where the hardware should be connected. Ideally we'd have top level pages for both the hardware and software side of the ultrasound to ensure that it is discoverable.

We should also mention the presence of the component and associated rainbow coloured connector wires in the hardware list.

There are some resources in an internal Slack thread on how to reply to teams who are asking about this in Discord. That links to the following pages:

• https://projecthub.arduino.cc/Isaac100/getting-started-with-the-hc-sr04-ultrasonic-sensor-7cabe1 for hardware connections
• https://howtomechatronics.com/tutorials/arduino/ultrasonic-sensor-hc-sr04/ for how the sensor works