Remove A0

Remove is an accellerometer for doing input shaping with Klipper.

Klipper configuration:

# The Remove resonance tester mcu
[mcu rp2040]
serial: /dev/ttyACM0
baud: 1500000

[adxl345]
cs_pin: rp2040:gpio5
spi_bus: spi0a

[resonance_tester]
accel_chip: adxl345
probe_points:
    100, 100, 20  # an example