Add endstops, light_sensor, test, many fixes

- Added endstop and light_sensor module
 - Improved configuration by splitting wiring configs to boards.h
 - Added a unit test for argument parsing
 - Fixed many smaller bugs

src/modules/light_sensor/light_sensor.h

@@ -0,0 +1,18 @@
+#include "config.h"
+#ifdef LIGHT_SENSOR
+#ifndef LIGHT_SENSOR_H
+#include <Arduino.h>
+
+void light_sensor_gain(String);
+void light_sensor_gain_values(String);
+void light_sensor_integration_time(String);
+void light_sensor_intensity(String);
+
+void light_sensor_setup();
+void setup_light_sensor_device();
+
+void print_light_sensor_gain();
+void set_light_sensor_gain(int);
+#define LIGHT_SENSOR_H
+#endif
+#endif