packet: add EVPN NLRI parser and serializer
packet: add EVPN NLRI parser and serializer

Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

tamihiro/gobgp,a16/gobgp,ishidawataru/gobgp,a16/gobgp,ramrunner/gobgp,tamihiro/gobgp,postfix/gobgp,YujiOshima/gobgp,a16/gobgp,ramrunner/gobgp,ishidawataru/gobgp,postfix/gobgp,osrg/gobgp,osrg/gobgp,Dipsingh/gobgp,postfix/gobgp,tamihiro/gobgp,fujita/gobgp,YujiOshima/gobgp,h-naoto/gobgp,a16/gobgp,fujita/gobgp,j-kato/gobgp,ramrunner/gobgp,h-naoto/gobgp,ishidawataru/gobgp,fujita/gobgp,j-kato/gobgp,a16/gobgp,osrg/gobgp,fujita/gobgp,h-naoto/gobgp,Dipsingh/gobgp,tamihiro/gobgp,a16/gobgp,Dipsingh/gobgp,j-kato/gobgp,osrg/gobgp,YujiOshima/gobgp,a16/gobgp