[#40827795] Add DataTab as a subview of WorkfileSidebar
[#40827795] Remove DatasetAndColumnList
[#40827795] Extract DataTabDataset view from DatabaseDatasetSidebarListItem
[#40827795] Rename DatabaseDatasetSidebarListItem to DataTabDatasetList
[#40827795] Use DataTabDatasets as subviews in DataTabDatasetList, instead of rendering the list elements directly from the parent