[IMP]model: Improved read_group method to display empty column result and folded columns from related model and default_group_by field will be automatically added to the kanban no need to declare in kanban to enable the button 'Add a new column'. pass options in the read_group, In options pass 'fold_field' and 'display_empty_column' fields and remove _group_by_full methods from crm, hr_recruitment, project, project_issue, survey, website_event_track, website_forum_doc modules.