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/i2c.c

@@ -34,7 +34,7 @@ void i2c_delay(void) {
   // _delay_us(100);
 }
 
-// Setup twi to run at 100kHz
+// Setup twi to run at 100kHz or 400kHz (see ./i2c.h SCL_CLOCK)
 void i2c_master_init(void) {
   // no prescaler
   TWSR = 0;