Rename '-h' option to '-p', and use "portal" instead of "host" or "address",
in order to be consistent with iSCSI terminology.  Besides, calling the
option '-h' was just wrong.

This changes usage for newly added iscsictl(8), and two newly added
subcommands to ctladm(8).  This breaks POLA between CURRENT and 10,
but since 10.0 has not been released yet, it's still ok to do.

MFC after:	3 days
Discussed with:	re (glebius)
Sponsored by:	FreeBSD Foundation
Bump .Dd after r257379.

MFC after:	3 days