LU-17741 gss: fix lsvcgss service for systemd

LU-17741 gss: fix lsvcgss service for systemd

Add a systemd unit file for lsvcgss service, so that the lsvcgssd
daemon can be handled correctly via systemctl.

Test-Parameters: trivial
Test-Parameters: kerberos=true testlist=sanity-krb5 clientdistro=el9.3 serverdistro=el9.3
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I7581996e1e28567415da0827681841ac228ad6c5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54915
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>