fs.FS interface types wrapper

[AndreRenaud]

I wrote this as a side effect of a separate command line tool I was working on, and it felt like it might be more widely useful.

See https://pkg.go.dev/io/fs for interface details

Example usage:

package main

import (
	"log"
	"net/http"
	"os"

	"github.com/t3rm1n4l/go-mega"
)

var USER string = os.Getenv("MEGA_USER")
var PASSWORD string = os.Getenv("MEGA_PASSWD")

func main() {
	m := mega.New()
	if err := m.Login(USER, PASSWORD); err != nil {
		log.Fatalf("Cannot connect to Mega: %s", err)
	}

	mux := http.NewServeMux()
	mux.Handle("/", http.FileServer(http.FS(m)))

	if err := http.ListenAndServe(":8000", mux); err != nil {
		log.Fatal(err)
	}
}

Then browse to http://localhost:8000 to see the content.

There aren't any tests yet (which there should be), but I thought I'd ask for feedback before cleaning everything up.