Convert tres values to corresponding units.

src/common/slurmdb_defs.c

src/common/slurmdb_defs.h

src/sacct/print.c

src/sacctmgr/cluster_functions.c

src/sacctmgr/common.c

src/sacctmgr/event_functions.c

src/sacctmgr/file_functions.c

src/sacctmgr/reservation_functions.c

src/slurmctld/reservation.c

src/slurmctld/step_mgr.c