separated edit_reservation to add, remove and modify

slurm/slurm.h.in

src/common/slurm_accounting_storage.c

src/common/slurm_accounting_storage.h

src/common/slurmdbd_defs.c

src/common/slurmdbd_defs.h

...s/accounting_storage/filetxt/accounting_storage_filetxt.c

...ugins/accounting_storage/mysql/accounting_storage_mysql.c

...plugins/accounting_storage/none/accounting_storage_none.c

...ugins/accounting_storage/pgsql/accounting_storage_pgsql.c

...accounting_storage/slurmdbd/accounting_storage_slurmdbd.c

src/slurmctld/reservation.c

src/slurmdbd/proc_req.c