NXP-15146: submit ajaxified forms on change/select/click on widgets demo and preview screens, and adapt selenium tests to new behaviour
NXP-15145: add demo for aggregate widget types + adapt pages to hide view mode (not supported by aggregates) (wip)
NXP-15146: control forms submit on change/select/click by widget configuration
NXP-15145: add more samples around select and directory widgets + tests