Documentation update

[s-wick]

The codebase has changed significantly since the last update to the documentation. One of the remarks from the design judges suggested documenting enough so that anyone could rebuild the entire system without prior knowledge of the codebase.

A list of changes to be made:

• Add a markdown file containing wiring instructions (to be used as reference when programming).
• Add systemctl commands to deploy the service.
• Add documentation about Telegraf
• Add telegraf.conf.example file
• Update requirements.txt