config.toml has mixture of zh and en references causing website issues

[sebbASF]

https://github.com/apache/dubbo-website/blob/a3bc6c46c78fb9088b27e8dd512e2e6be381707b/config.toml#L11

There is a single config.toml file which defaults to zh but has some en references.

This leads to various incorrect links on the website.

For example, the Releases dropdown on https://dubbo.apache.org/en/ leads to pages under zh/docs.