rbd: promote rbd-nbd attach and detach at rbd integrated cli

rbd: promote rbd-nbd attach and detach at rbd integrated cli

Example:
$ rbd device attach rbd-pool/image --device /dev/nbd0 --device-type nbd --force
$ rbd device detach rpool/image --device-type nbd

for now returning EOPNOTSUPP with krbd, ggate and wnbd

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
(cherry picked from commit 35e5352f719857bed99caa4c76ae19bb68918c8e)

Conflicts:
	src/tools/rbd/action/Device.cc [ commit e1b4811bc324 ("rbd: add
	  missing switch arguments for recognition by get_command_spec()")
	  already in pacific ]
	src/tools/rbd/action/Wnbd.cc [ ditto ]