Possibility for survey respondent to get a summary of their answers

Is your feature request related to a problem? Please describe.
Right now Decidim does not allow survey respondents to get a summary/list of their answers to a survey. In some occasions it would be useful for the respondents to get such information either through the survey answer page or automatically to their email or both.

Describe the solution you'd like
The survey component should provide a configuration option which would allow the survey respondents to get a summary of their answers after they responded to the survey.

In case the survey respondent was signed in to the service, the summary would be sent to the email address associated with their account. In case the survey allows anonymous answers, the survey response page could show an email box after the user responded to the survey allowing them to order the list to their email.

Or alternatively, there could be also a button on the survey answer page through which the user could download a list of their own answers.

Describe alternatives you've considered
Custom code which hooks into the survey answer action but that might be complicated.

Additional context
This proposal came from a concrete customer enquiry where the customer asked if this kind of functionality is already part of Decidim.

Does this issue could impact on users private data?
For anonymous answers, it could have an effect since we need to ask the user their email in order to send the data there. But on that page we could clearly indicate that the email is only used to send the summary to their email box and nothing else.

Possibly also next to the email box we need to show some brief information about the privacy policy of the service and how their email is processed and utilized. In its simplest form, it could be only a link to the privacy policy page where this is explained.

Funded by
Right now we do not have anyone willing to fund this, so just documenting this request here for future consideration.