Specify the way tables should be handled in Nuxeo Studio

There are currently major discrepancies in the way tables are handled from one screen to another, ex:

• You need to right click in the vocabularies screen to remove an entry
• You need to explicitly add columns in the form layouts to add a widget, but not in tabs (that also rely on a specific grid system)

=> write specs so that all screens could behave the same way and provide a consistent user experience