LU-5868 nodemap: Add nodemap_info to lctl

LU-5868 nodemap: Add nodemap_info to lctl

This patch adds nodemap_info to lctl, which can list all defined
nodemaps and display information about them, such as idmaps, ranges,
and flags. It is implemented as a wrapper to get_param/list_param,
and adds a -D parameter to list_param to only show directories.

Signed-off-by: Kit Westneat <kit.westneat@gmail.com>
Change-Id: I5d5ac44ec30bad49878be76168954dd231656421
Reviewed-on: http://review.whamcloud.com/13044
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>