LU-8998 llapi: rename llapi_layout_comp_move -> *use

LU-8998 llapi: rename llapi_layout_comp_move -> *use

Rename llapi_layout_comp_move() and llapi_layout_comp_move_at()
to llapi_layout_comp_use() and llapi_layout_comp_use_id(),
respectively.  This avoids confusion about what "move" and "at" in
the function name implies. The component itself is not actually
being moved, just a different layout component is being selected
for access or modification.  Using "_id" instead of "_at" also
makes it more clear what the difference is between these functions.

Rename LLAPI_LAYOUT_COMP_POS_{FIRST,NEXT,LAST} correspondingly to
LLAPI_LAYOUT_COMP_USE_{FIRST,NEXT,LAST} to match.

Split llapi_layout_comp_use_id.3 from llapi_layout_comp_use.3 since
they are mostly independent anyway.

Test-Parameters: trivial testlist=sanity-pfl
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I85926d4ec9774745bc49b0d178ed9b23ec2cab07
Reviewed-on: https://review.whamcloud.com/26483
Tested-by: Jenkins
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>