Fix arduino workflow

[simoneengelbr]

There is not currently a workflow testing Arduino files when they are updated.

This should be implemented. A basic test to perform would be whether Sensor Node code can compile to an Arduino UNO, and Control Panel code to an Arduino Mega 2560.

There are several ways to test this, eg. arduino-cli or Travis CI.

However, all alarm device files use external libraries, namely https://github.com/matthijskooijman/arduino-lmic and http://www.forward.com.au/pfod/SipHashLibrary/. So far, no way of importing external libraries as part of a workflow has been determined using either arduino-cli or Travis CI.