Cleanup: removed using namespace from header files

src/entrypoints/dma-lowlevel-test.cpp

src/shared/canbus/CanBus.cpp

src/shared/canbus/CanBus.h

src/shared/canbus/CanInterrupt.cpp

src/shared/canbus/CanManager.cpp

src/shared/canbus/CanManager.h

src/shared/sensors/ADC.h