Add driver for ST vl53l0x time of flight sensor.
This driver can be used in 2 modes :
* proximity sensor :
configure VL53L0X_PROXIMITY_THRESHOLD
will return 1 if target is between sensor and threshold,
else, 0
* distance sensor :
will return the distance in millimeters from sensor to target
This driver use the official STMicroelectronics library for vl53l0x.
(in ext/hal/st/lib/sensor/vl53l0x)
Signed-off-by: Vincent Veron <vincent.veron@st.com>