Merge pull request #6665 from aabadie/driver_veml6070

drivers/Makefile.dep

drivers/Makefile.include

drivers/include/veml6070.h

drivers/veml6070/Makefile

drivers/veml6070/include/veml6070_params.h

drivers/veml6070/veml6070.c

drivers/veml6070/veml6070_saul.c

sys/auto_init/auto_init.c

sys/auto_init/saul/auto_init_veml6070.c

tests/driver_veml6070/Makefile

tests/driver_veml6070/Readme.md

tests/driver_veml6070/main.c