Moved all system commands to new build system

apps/systemcmds/calibration/Makefile

apps/systemcmds/calibration/calibration.c

apps/systemcmds/calibration/calibration.h

apps/systemcmds/calibration/channels_cal.c

apps/systemcmds/calibration/range_cal.c

apps/systemcmds/calibration/servo_cal.c

apps/systemcmds/top/Makefile

makefiles/config_px4fmu_default.mk

makefiles/config_px4fmuv2_default.mk

src/modules/mavlink_onboard/module.mk

src/systemcmds/bl_update/bl_update.c

src/systemcmds/bl_update/module.mk

src/systemcmds/boardinfo/.context

src/systemcmds/boardinfo/boardinfo.c

src/systemcmds/boardinfo/module.mk

src/systemcmds/eeprom/module.mk

src/systemcmds/i2c/i2c.c

src/systemcmds/i2c/module.mk

src/systemcmds/mixer/mixer.c

src/systemcmds/mixer/module.mk