nft: adds save_matches_and_target

This patch permits to save matches and target for ip/ip6/arp/eb
family, required for xtables-events.

Also, generalizes nft_rule_print_save to be reused for all protocol
families.

Signed-off-by: Giuseppe Longo <giuseppelng@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
6 files changed