support multi-module (#4)

* add multimodule
* re-package modules

server/cmd/http/main.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/iliadenisov/galaxy/server/internal/router"
+)
+
+func main() {
+	r := router.NewRouter()
+	if err := r.Run(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}