Add time window for sep schedule scans

See merge request gitlab-org/gitlab!174596



Merged-by: Alexander Turinske <aturinske@gitlab.com>
Approved-by: Andy Schoenen <asoiron@gitlab.com>
Approved-by: Alexander Turinske <aturinske@gitlab.com>
Reviewed-by: Andy Schoenen <asoiron@gitlab.com>
Reviewed-by: Alexander Turinske <aturinske@gitlab.com>
Reviewed-by: Sashi Kumar Kumaresan <skumar@gitlab.com>
Co-authored-by: mc_rocha <mrocha@gitlab.com>