Getting started instructions are missing auth provider setup

Currently, getting started instructions are missing the steps to configure the auth provider. We're referencing our live documentation, which unfortunately isn't working, because it's incompatible with this SDK. To help developers try this SDK, we should include a fully working sample, for example:

import { ClientSecretCredential } from '@azure/identity';
import { AzureIdentityAuthenticationProvider } from '@microsoft/kiota-authentication-azure';
import { FetchRequestAdapter } from "@microsoft/kiota-http-fetchlibrary";
import { createGraphServiceClient } from "@microsoft/msgraph-sdk";
import "@microsoft/msgraph-sdk-users";
import 'dotenv/config';

(async () => {
  const credential = new ClientSecretCredential(
    process.env.TENANT_ID,
    process.env.CLIENT_ID,
    process.env.CLIENT_SECRET
  );
  const authProvider = new AzureIdentityAuthenticationProvider(credential, ['https://graph.microsoft.com/.default']);
  const requestAdapter = new FetchRequestAdapter(authProvider);
  const graphServiceClient = createGraphServiceClient(requestAdapter);

  try {
    const users = await graphServiceClient.users.get();
    console.log(JSON.stringify(users));
  }
  catch (error) {
    console.error(error);
  }
})();

Locate the getting-started instructions and review how authentication is currently described. Add a fully working TypeScript auth-provider setup compatible with this SDK, including the sample flow shown in the issue, and verify that the instructions let developers run the users request successfully.