Raspberry Pi family heating test.
To start running a test, set an environment variable called RUN (either device or service
variable for the main service). Then the application starts the data recording and shows
the saved fileaname testrun.YYYYMMDD_HHmmss.csv format. After a 30s delay, it will start
a stress --cpu 8 thread to stress the device, and will start tailing the data file.
To stop the test, just delete the RUN env var.
If you enable device public URL, there you can find a web server to download the recorded files at /.
Also, if you go to /plot/, you can see the relevant .csv files, and have an option to quick plot
the recording as well.