Make the contents in a dataformat collapsible

The dataformats can become very complicated and big very fast. A way to make it easier for the user to deal with this amount of data is to make the content part in each category added to a dataformat collapsible so the user can have an overview of what is in the dataformat before going into details of each part of it.

This is to make it easier for the user to deal with big objects in the editor by handling the visual aspects of the editor in a better way. See #235 (closed)