Abstract device under test peripherals

[tdittr]

Currently we list out all possible peripherals in a struct. This is not very ergonomic especially when peripherals might not be implemented or parts need to be reused. We should just have a trait to abstract the device under test.

For example:

pub enum Pin {
    D0,
    D1,
    D14,
}

pub trait DeviceUnderTest {
    fn get_output(&mut self, pin: Pin) -> Result<impl OutputPin, ()>;
    fn get_i2c(&mut self) -> Result<impl I2c, ()>;
}