openwrt配置中国电信宽带IPv6

2019年新hg200gs光猫配置：

https://www.dispnt.com/index.php/archives/45/

参考：

https://www.cnblogs.com/osnosn/p/11781359.html

https://lwz322.github.io/2019/07/25/IPv6_Home.html

https://v2ex.com/t/530084

https://www.right.com.cn/forum/thread-578603-1-1.html

https://www.right.com.cn/forum/forum.php?mod=viewthread&tid=556524