What your describing is essentially a business analyst, albeit a technically minded in whilst not being a developer. I consider myself of the same ilk and I think the best thing you can contribute is input and UX/UI design, sanity checking of ideas, feedback from users etc.

The facilitation role between users and developers is so much more than 'documentation' which alot of the comments in this thread seem to suggest.

I suggest contacting a few of the projects listed here, or any you find on GitHub you'd like to contribute to and just offer to help.