Initial framework for adding an OpenAI token to the base config

[mcncl]

We don't need to have the functionality yet, but the initial field could be set on first config right now.

We'll need to check for its existence to replace the empty string in the future.

I can see a future where each org may have its own token, but at the moment a top level makes sense to me; we can always change it later.

[jradtilbrook]

👌