LU-9680 utils: add updating the key table for Netlink.

LU-9680 utils: add updating the key table for Netlink.

Currently lnetconfig implementation only sends the key table once
to construct a YAML document. Add the ability to update the key
table at a latter time. New keys will be used by the YAML
document.

Test-Parameters: trivial
Change-Id: Ie2201f91eb24d06c7e2a2d4abe3da3805f74e5a7
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51715
Tested-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>