[Feature] Add custom facts example

[datorr2]

Use Case

Not sure where/how to get started with developing custom facts using this control repo.

Describe the Solution You Would Like

An example/starter for a custom fact would be beneficial for users of this control repo. They would not only know where the facts should reside, but also the basic syntax to get started.

Describe Alternatives You've Considered

Lots of internet searches, but not having any luck thus far. :/