AUI-1698 Empty columns should be removable

Also fixed bug where moved columns would not have the `remove` button.
AUI-1694 Add label atribute to Data Editor
AUI-1694 Create grid field
AUI-1694 Source formatting
AUI-1693 Create a Scale Data Editor
AUI-1693 Create scale field
AUI-1693 Source formatting

All functions related to the `label` attribute are now inside aui-data-editor, so they don't need to be here anymore.
AUI-1711 Improve interaction of adding new rows