Improve support for listings in folderish doctypes

View layouts for folderish doctypes are scaffolded using nuxeo-document-content, however, it is not possible to use the wysiwyg editor to configure the columns used for listings, and it is not a very easy task to do that in html too.

We should improve the scaffold for folderish doctypes maybe by using the nuxeo-results with support for column selection and configuration using the wysiwyg editor, or through html editing.