Add a YAML template that just focuses on the questions (and maybe attachment block)

[nonprofittechy]

Sometimes someone wants to get the questions and attachment block to integrate a new file into an existing interview. We should make this easier to do without manually deleting a lot of stuff out of the generated YAML file.

[nonprofittechy]

Possibly, it should also be made easier to upload a list of variables to skip making questions for--ones that are already defined in the existing interview.