Enhance ipinfoLocal.mmdb file lookup

[breakertt]

Both source code and documents are updated, however, I only tested on Linux environment.

[tsosunchia]

Good job
但是为了统一环境变量的读取方式，
需要修改这部分代码

envIPInfoLocalPath := os.Getenv("NEXTTRACE_IPINFOLOCALPATH")

需要放在这个文件里https://github.com/nxtrace/NTrace-V1/blob/main/util/util.go
并参考该文件中19行附近的代码

非常感谢您的工作

[breakertt]

Thanks a lot for your quick reply, I have made the refactor you requested.

[tsosunchia]

Searching for ipinfoLocal.mmdb in these folders: [/root/ /root/ /usr/local/share/nexttrace/ /usr/share/nexttrace/]
目前的默认行为是显示这条日志，是不是不显示更好一些呢？

[breakertt]

Sorry it is meant to be debug only, I should have removed it before committing.

[tsosunchia]

根据 ACTIONS 的自动检查，ipgeo/ipinfoLocal.go 中需要修改

"fmt" imported and not used

[breakertt]

Sorry fixed

[tsosunchia]

well done