Consider using `goversioninfo` to embed info on Windows binaries

[francislavoie]

We had a user on the forums confused as to what version of Caddy they downloaded because they didn't see a version number in the properties of the .exe file.

See https://github.com/josephspurrier/goversioninfo, we can probably use that to embed version info and a link to the docs, I guess. Ideally it just works automatically without any user input when GOOS is windows.

[mholt]

Neat, ok, that might be possible. Thanks!