Only include used project credentials when exporting the project.yaml

[midigofrank]

• We only need to include credentials that are being used when doing a cli pull. This would touch the porject.yaml and state.json.
• This should apply to the export project button in the project settings page. For this button I actually think we should provide an option to avoid adding any credential at all.

I will add the background details later, but you can read: OpenFn/kit#1268