[spi] Updated SPI driver with new low level driver

src/shared/drivers/spi/SPI.h

src/shared/drivers/spi/SPIBus.h

src/shared/drivers/spi/SPIBusInterface.h

src/shared/drivers/spi/SPISignalGenerator.h

src/shared/drivers/spi/SPITransaction.cpp

src/shared/drivers/spi/SPITransaction.h

src/shared/utils/testutils/MockGpioPin.h

src/tests/drivers/spi/test-spi.cpp