A survey has been filled in and submitted.
Fetch list of handlers for survey submits.
Check if the current user is allowed to download a survey.
Check if a question is a submitting question.
Modify row with answers for export. The header columns are given and the
values that are known are set in the folded value. The user_id is the user who
Add header columns for export. The values are the names of the answers and
the text displayed above the column. The text format is for a complete export, the…