Feature request: allow collapsing on Manage fields and Manage display pages

[laryn]

I have a number of content types with a long list of fields in various groups, and reordering things is a real headache. I don't know if it would be possible on this page, but I had a thought that if a group of fields is already grouped perhaps we could allow them to be visually collapsed (like Paragraphs does I suppose) so that reordering can be simplified into moving groups of fields around without all the clutter of the fields within the groups.