Make I2C pins configurable on ESP32

include/config_pins.h

 #define SWITCH_COUNT 2
 #define SWITCH_PINS 22, 23
 
+#define I2C_SDA_PIN 21
+#define I2C_SCL_PIN 22
+
 #endif // FUNCTION_CONTROL
 
 #endif // PLATFORM_ESP

src/Functionality.cpp

     
     debug.println("Initializing I2C Master");
     Wire.setClock(I2C_BUS_SPEED);
+    
+#if defined(I2C_SDA_PIN) && defined(I2C_SCL_PIN)
+    Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);
+#else
     Wire.begin();
+#endif // defined(I2C_SDA_PIN) && defined(I2C_SCL_PIN)
     
 #ifdef DEBUG_WAIT_FOR_SERIAL_CONN
     debug.println("Wait for Serial");