Add large replay widow support to setkey(8) and libipsec.

When the replay window size is large than UINT8_MAX, add to the request
the SADB_X_EXT_SA_REPLAY extension header that was added in r309144.

Also add support of SADB_X_EXT_NAT_T_TYPE, SADB_X_EXT_NAT_T_SPORT,
SADB_X_EXT_NAT_T_DPORT, SADB_X_EXT_NAT_T_OAI, SADB_X_EXT_NAT_T_OAR,
SADB_X_EXT_SA_REPLAY, SADB_X_EXT_NEW_ADDRESS_SRC, SADB_X_EXT_NEW_ADDRESS_DST
extension headers to the key_debug that is used by `setkey -x`.

Modify kdebug_sockaddr() to use inet_ntop() for IP addresses formatting.
And modify kdebug_sadb_x_policy() to show policy scope and priority.

Reviewed by:	gnn, Emeric Poupon
Differential Revision:	https://reviews.freebsd.org/D10375