Adding `request_disk` parameter to HTCondor .sub files

The request_disk parameter is no longer optional for HTCondor .sub files on the LIGO clusters. We have added a placeholder `request_disk = 1 GB" to all .sub files, and jobs are now running successfully.

1GB may be overkill, and we should really be working on a sliding scale based on the rest of the settings. RIFT is apparently using 4MB without issues, though they may hit that limit after further usage.