Custom USB VID/PID for sprig

[devramsean0]

Problem

Some networks block USB devices from connecting and sometimes flag them if they aren't whitelisted (Mine for example),
However, IT admins are probably more likely to unblock Sprig if they can just unblock sprig, instead of unlocking most RP2040's with firmware built by the pico SDK

Solutions

1. We get a USB PID using the Raspberry PI Vendor ID (process is documented on their GitHub) - Costs nothing
2. We get our own VID so we can issue our own PID's - Could be helpful for also doing it for blot & orpheus pico & any other micro controller based project, but costs $6k from the USB IDF

Actual implementation

We just add:

#define USB_VID (<VID here>) // If we get our own VID
#define USB_PID <PID here>)