LU-18151 contrib: add example Coccinelle scripts

LU-18151 contrib: add example Coccinelle scripts

Add a few example Coccinelle scripts to contrib/. Also,
update clang-and-static-analysis.txt to talk about
Coccinelle.

Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: I9a09b2f273bb2257e67c253cb3a69896c32d588a
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56073
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Patrick Farrell <patrick.farrell@oracle.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: jsimmons <jsimmons@infradead.org>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>