Add support for Linux IIO sensor devices

[amotl]

Hi there,

at [1], started by @MKO1640, we are discussing what it would take to support reading measurement values from Linux IIO devices. @MKO1640 unlocked the hardware drivers for the HX711, NAU7802 and BME280 sensors the other day (thanks!).

At [2], there are some example implementations. Those snippets can be used for conceiving a sensor adapter for Terkin.

With kind regards,
Andreas.

[1] https://community.hiveeyes.org/t/erschliessung-des-hx711-treibers-fur-linux-iio/4091
[2] https://github.com/analogdevicesinc/libiio/tree/master/bindings/python/examples