dev(fs): add move command to batch executor

[KernelDeimos]

Effectively this makes it possible to perform multiple move operations in a batch request.

Example:

(async () => {
  const form = new FormData();

  const operations = [
    {
      op: "move",
      source: "/admin/Desktop/first.txt",
      destination: "/admin/Desktop",
      new_name: "second.txt"
    }
  ];

  for (const op of operations) {
    form.append("operation", JSON.stringify(op));
  }

  const res = await fetch("http://api.puter.localhost:4100/batch", {
    headers: {
        Authorization: `Bearer ${puter.authToken}`,
    },
    method: "POST",
    body: form,
  });

  console.log("response:", await res.json());
})();