LU-10391 lnet: migrate router management to Netlink

LU-10391 lnet: migrate router management to Netlink

Add the doit Netlink handling for routes. The creation and
deletion of routes can now work with large NIDs using the
Netlink API.

Test-Parameters: trivial testlist=sanity-lnet
Change-Id: Ia9fc64785962ce3e74abeef9c77e8b2df0789dd7
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50254
Reviewed-by: Frank Sehr <fsehr@whamcloud.com>
Reviewed-by: Chris Horn <chris.horn@hpe.com>
Reviewed-by: Cyril Bordage <cbordage@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>