drv/ioport: share ioport code

This refactors the ioport driver code so that it can be shared by all LPF2 platforms. The device connection manager has also been refactored to use protothreads instead of a state machine.

It also introduces a new GPIO driver that could also be used by other drivers.

movehub fw size -40

bricks/stm32.mk

@@ -147,13 +147,15 @@ HAL_SRC_C = $(addprefix lib/stm32lib/STM32F$(CPU_FAMILY)xx_HAL_Driver/Src/,\
 PBIO_SRC_C = $(addprefix ports/pybricks/lib/pbio/,\
 	drv/adc/adc_stm32f$(CPU_FAMILY).c \
 	drv/battery/battery_adc.c \
+	drv/gpio/gpio_stm32f$(CPU_FAMILY).c \
+	drv/ioport/ioport_lpf2.c \
 	drv/$(PBIO_PLATFORM)/bluetooth.c \
 	drv/$(PBIO_PLATFORM)/button.c \
 	drv/$(PBIO_PLATFORM)/light.c \
-	drv/$(PBIO_PLATFORM)/ioport.c \
 	drv/$(PBIO_PLATFORM)/motor.c \
 	drv/$(PBIO_PLATFORM)/uart.c \
 	platform/$(PBIO_PLATFORM)/clock.c \
+	platform/$(PBIO_PLATFORM)/platform.c \
 	platform/$(PBIO_PLATFORM)/sys.c \
 	src/motor.c \
 	src/error.c \