Move perfusion or add a "terminal_procedure_details" section

Some scientists have pointed out that the Surgery>Perfusion setup is a bit clunky, and most (or possibly all) perfusions happen wrapped in a surgery that has no other details. If that's the case, we might want to elevate the perfusion details into their own field, renamed to also cover deaths for other species? This would make it easier to access those details without having to search the surgery list for the perfusion object.