LU-8066 fld: move all files from procfs to debugfs

Port of the upstream client work done by Dmitry Eremin.

Linux-commit: 827650494fbe9390052502d0498c8b90b2e329ec

Move all server side procfs handling to debugfs.

Change-Id: I6b0311d148576dec1ab1ef7ca1afce0ab2e4ed3b
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Signed-off-by: Dmitry Eremin <dmiter4ever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-on: https://review.whamcloud.com/26651
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>