Add default value for `representative_approved` column.
Add default value for `representative_approved` column.

A default column was missing what resulted in a service which could
not be saves because a validation error occurred and was not visible
if you tried to save the service with type=institute.

SURFnet/sp-dashboard,SURFnet/sp-dashboard,SURFnet/sp-dashboard,SURFnet/sp-dashboard,SURFnet/sp-dashboard