Add support for resetting RP2040 via the USB connection when using pico_stdio_usb

- setting baud rate to magic value (default=1200) will cause a reset to BOOTSEL mode
	- a VENDOR interface along side the CDC interface can be used to reset via refular flash boot, or into
	  BOOTSEL mode with control for the reset_usb_boot parameters for the latter
either method can be configured/enabled/disabled via #define

src/rp2_common/pico_stdio_usb/stdio_usb.c

@@ -8,7 +8,6 @@
 #include "tusb.h"
 
 #include "pico/time.h"
-#include "pico/stdio_usb.h"
 #include "pico/stdio/driver.h"
 #include "pico/binary_info.h"
 #include "hardware/irq.h"