BibSched: improve low level submission arg parsing
BibSched: improve low level submission arg parsing

* runtime, sleeptime, and name arguments are now recognized
  in task_low_level_submission().
  (closes #209)

Co-authored-by: Samuele Kaplun <2e218f779e12714c314fad8ebf6b3041daa21337@cern.ch>

tiborsimko/invenio,tiborsimko/invenio,inveniosoftware/invenio,inveniosoftware/invenio