Replacing GoProxy for native Git or private host

[oscarvalenzuelab]

While we implemented a workaround to use goproxy.io instead of proxy.golang.org, we should enable a config to use native Git instead of goproxy as Go supports "direct".

ref:

• https://github.com/goproxyio/
• https://github.com/thumbai/thumbai

[oscarvalenzuelab]

Some other examples: https://github.com/microsoft/OSSGadget/blob/f8ac740e99fdb25057ab6539caaf053f1022692d/src/Shared/PackageManagers/GolangProjectManager.cs#L21