This adds several previously missed but important subcommands to list
namespaces and controllers. It also fixes few previously added but
just found with real testing to be broken subcommands.
Also while there, add possibility to explicitly specify nsid for
`nvmecontrol identify` subcommand. It may be useful to specify nsids
not having own devices, for example 0xffffffff, or just newly created
ones.
MFC after: 2 weeks
Relnotes: yes
Sponsored by: iXsystems, Inc.
Rename print_controller to nvme_print_controller. Put it in its
own file for easy inclusion. Move util.c to be nc_util.c to not
conflict with camcontrol. add nvecontrol_ext.h to define shared
interfaces.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D15371
