docs: add English blog section with translated posts

docs: document rejectUnknownSNI, sniffing.dialOriginalDst

- rejectUnknownSNI + serverNames TLS config (gost#864): zh/en tutorials + config ref
- sniffing.dialOriginalDst redirect flag (x#115): zh/en ref pages + tutorial note

update reverse proxy

add concepts/forwarder.md

update tutorial/proxy-protocol.md

update tungo.md

update api/config

update tutorials/sniffing

update tutorials

update recorder