datura: automatically resubmit if terminated due to walltime

This patch adds code to datura's run script that detect if the run was terminated due to walltime running out. In that case it will resubmit the job automatically.

This is an alternative over presubmission which is often more convenient for the user in case simulations fail. Presubmission itself would benefit by Cactus returning a failure code (that simfactory would need to forward) when termination is triggered by an error.