commands: start a new internal sub-package for working with json commands
commands: start a new internal sub-package for working with json commands

This code was part of cephfs/admin but will be shared with a soon-to-be
rbd/admin package.

Signed-off-by: John Mulligan <eda8ad33169deab44f9fe65847f99e368da6c91b@redhat.com>

ceph/go-ceph,ceph/go-ceph,ceph/go-ceph