Support multiple widgets in single table cell

In some cases we have multiple widgets in single table cell - e.g. 2 buttons in 'Actions' column, but currently Table widget supports only 1 widget per column.
We can try to workaround that by moving those widgets into separate view and assigning that view to table cell, but that will create some boilerplate (not to mention no one tried it out so no guarantees it will actually work :) ).
Ideally i just want to be able to specify some dict with widgets per table column, e.g:

resources = SatTable(
    locator='//table',
    column_widgets={
        'Version': Text('.//a'),
        'Status': PublishPromoteProgressBar(),
        'Actions': {'clone': Button(id='clone'), 'delete': Button(id='delete')}
    },
)

Start by locating the SatTable implementation and how its column_widgets mapping currently resolves one widget per column. Trace the existing table-cell and widget handling before deciding how the shown nested mapping should be represented. Done means a column such as Actions can expose both clone and delete buttons while existing single-widget columns continue to work.