Create an Architecture Document for the Project Providers

[niACS]

Is your feature request related to a problem? Please describe.
There is no documentation for the Actor Framework Project providers, which is an impediment to collaborative development.

Describe the solution you'd like
Provide an editable document describing the structure and implementation of the Actor Framework Project Providers.

Describe alternatives you've considered
I gave a one-hour presentation on this topic at the 2019 CLA Summit, which is available on YouTube. I considered leaving it at that, but video makes a poor reference, and we can't edit the content as the providers evolve.