LU-8191 utils: remove unused, fix non-static functions

LU-8191 utils: remove unused, fix non-static functions

Remove several functions which are never called.

Static analysis shows that a number of functions
could be made static. This patch declares several
functions in various Lustre utils static.

Some missing headers caused some functions being
incorrectly marked as possible candidates for
being made static. These missing headers have
been added.

Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: Id51f922be57c33c011ee2f9e509ca164cc480edf
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51439
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>