feat: Basic implementation of google sign-in

[yuyu0227]

Description

What new features or functions does this PR provide? What bugs does it fix?

• Overall: implement the google sign-in following https://developers.google.com/identity/sign-in/web/sign-in
• frontend: Create a component "Login" using library "react-google-login";
  send accessToken to backend server by "api/test/google"
• backend: Get accessToken from "api/test/google" and use accessToken to get user profile from Google

Testing

How did you test the code in the pull request?

• test in Storybook; test in Safari/Chrome/Safari private mode

Checklist

• I provided a description of the contents of this pull request.
• I've linked this pull request to an issue.
• I've assigned myself as the Assignee and labelled the PR correctly.

[joshmhanson]

The merge conflict is complaining about the OAuth2 dependency I introduced in a previous commit. It's not clear yet how Google Sign-In will integrate, but we might end up reverting the OAuth2 dependency. We definitely need to keep the spring-boot-starter-security dependency however so be sure not to delete that when resolving conflicts.