Allow data set questions to be on the same page with non collection questions

[DennisFriedl]

Wanted

We want to display a non collection question set with general questions and a collection question set for data set questions on a single page. The data sets should of the "tabs" kind (nameable, selectable and available in the whole interview). See this mock image (imagine the header "Fragen pro Datenset" the same size as "Allgemeine Fragen"):

Currently

The current behaviour when you nest a collection question set into another question set, is that the collection question set isn't of the wanted "tabs" style but of the "block" style (like marking a single question as a collection). See this image:

Affected

Users and Managers

[jochenklar]

Thanks for the issue, this should part of the general rework of the interview next year.