Update dtdphi dag submit requirements; allow singularity

This MR updates the options in the dtdphi dag's condor submit files to allow use of a singularity container. It also updates the accounting group user to the O4 name, and slightly lowers the memory requests to encourage faster matches with nodes.

We have been asked to get this merged for the Early Warning code review, since this is the branch we used for generating the dtdphi files. We intend to work on a followup merge request to parallelize the final job in the dag, and automatically add cluster-specific requirements from the site profiles.

As a sanity check, I generated a new dag with no modifications beyond what is in this MR. If desired, that can be seen on CIT here: /home/cort.posnansky/dtdphi_dag_check