core: setup go module

cmd/service/main.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+func main() {
+	if err := run(os.Args, os.Stdin, os.Stdout); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run(_ []string, _ io.Reader, _ io.Writer) error {
+	return nil
+}