Keyboard: Improvement of crkbd communication functions (based on helix-keyboard) (#3798)

* improvement of crkbd communication functions (based on  helix-keyboard)

* Removed unnecessary code.

* Changed read restriction from #define to #pragma once.

* Changed from sizeof to defined size.

* moved lib folder to crkbdroot.
removed warning of ws2812.d

keyboards/crkbd/rev1/split_util.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <stdbool.h>
+#include "eeconfig.h"
+
+#define SLAVE_I2C_ADDRESS           0x32
+
+extern volatile bool isLeftHand;
+
+// slave version of matix scan, defined in matrix.c
+void matrix_slave_scan(void);
+
+void split_keyboard_setup(void);
+bool has_usb(void);
+
+void matrix_master_OLED_init (void);