Feature Request: Host checker cleanup and documentation

[robertjensen]

The current host checker system is currently a bit messy and hard to setup for outsiders.

We should cleanup and document this code much better:

• https://github.com/CINF/machines/blob/master/rasppi42/host_status.py
• https://github.com/CINF/PyExpLabSys/blob/master/PyExpLabSys/common/system_status.py
• https://github.com/CINF/cinfdata/blob/master/cinf_common/host_checker.php