[Feature] Support Proxy Protocol

[xzycn]

Verify steps

• [X] 我已经在 Issue Tracker 中找过我要提出的请求 I have searched on the issue tracker for a related feature request.
• [X] 我已经仔细看过 Documentation 并无法找到这个功能 I have read the documentation and was unable to solve the issue.

Description

When we put mihomo behind a LB, we cannot get a client IP. Thanks.

Possible Solution

github.com/pires/go-proxyproto

[xishang0128]

We won’t support it. This is not what mihomo should do.

[xzycn]

I see, thanks for your fast reply.