Add large replay widow support to setkey(8) and improve setkey's debugging

[ae]

Summary

rS309144 added support for large replay window, but setkey(8) and libipsec lacks this support.
This patch adds support of new sadb_x_sa_replay extension header to libipsec and setkey(8).
setkey(8) can set replay window for SA using '-r' option. When the replay window size is large than 255 bytes, we should add SADB_X_EXT_SA_REPLAY extension header.

Also extend setkey's debugging support. setkey -x can be used like tcpdump for PF_KEY's traffic. Add support for several new extension headers and NAT-T headers. In kdebug_sadb_address() use inet_ntop() for IP address formatting instead of using less readable hexdump.

[emeric.poupon_stormshield.eu]

Thanks for completing the job!