Add participant short_id to the survey response to ensure identification of responses

Currently the response and participant are only connected through the internal LimeSurvey access token. The researchers needs to ensure to also export the participant details with the response in the data export, which is a manual step. It would be good to, by default export this data with the response. I'm not exactly sure whether this belongs here but one option is to always add the participant_short_id as a hidden question/attribute in the response. It could also just be a matter of good documentation or setting the right defaults in limesurvey.