Add firmware code to repo (#8)

* Added primary stepper motor driver code to repo
* Added odometery encoder code to repo
* Added the ability to update encoder wheel ratio via ros service
Co-authored-by: Pimpest <82343504+Pimpest@users.noreply.github.com>
Co-committed-by: Pimpest <82343504+Pimpest@users.noreply.github.com>

firmware/base/src/stepper.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "hardware/pio.h"
+
+void stepper_init();
+void start_pulse(PIO pio, uint sm, uint offset, uint pin, uint freq);
+
+void update_sm(PIO pio, uint sm, const uint pin, double v);
+void set_speeds(double vl, double vr);