Promote filefs to stock Go

[mcandre]

Thank you for implementing a file:// handler for fs.FS URL's.

I find it ridiculous that Go fails to implement fs.FS for the local filesystem.

Petition to promote such an implementation directly into the Go standard library.

[hairyhenderson]

@mcandre this isn't the place for such a request - I'm not associated with the Go development team and it's unlikely that this will go anywhere.

See https://github.com/golang/proposal#readme for the right way to propose adding things to the Go standard library!