move pca8574 driver to lights

boards/auav/x21/default.cmake

boards/av/x-v1/default.cmake

boards/gumstix/aerocore2/default.cmake

boards/px4/fmu-v3/default.cmake

boards/px4/fmu-v3/rtps.cmake

boards/px4/fmu-v3/stackcheck.cmake

boards/px4/fmu-v4pro/default.cmake

boards/px4/fmu-v4pro/rtps.cmake

boards/px4/fmu-v5/default.cmake

boards/px4/fmu-v5/rtps.cmake

boards/px4/fmu-v5/stackcheck.cmake

boards/stm/nucleo-F767ZI/default.cmake

src/drivers/lights/CMakeLists.txt

src/drivers/lights/pca8574/CMakeLists.txt

src/drivers/lights/pca8574/pca8574.cpp