corosync-qnetd: Add resource agent

Mostly for better monitor operation using corosync-qnetd-tool. As qnetd
is (almost) stateless only directory which has to be copied (once)
across the nodes is nss db directory (usually
/etc/corosync/qnetd/nssdb).

Signed-off-by: Jan Friesse <jfriesse@redhat.com>