Add “Sign in with Google” Authentication

[nihams]

Currently, users can only register or log in manually through the authentication form. This can be time-consuming and discourages quick onboarding

Adding Google Sign-In will provide a faster and more secure way for users to sign-in

Integrate Google Authentication using OAuth 2.0 so users can sign in or sign up with their Google account in one click.

Kindly assign the gssoc and level label

[github-actions]

Thank you for raising this issue!

We'll review it as soon as possible. We truly appreciate your contributions! ✨

Meanwhile make sure you've visited the README.md, CONTRIBUTING.md, and CODE_OF_CONDUCT.md before creating a PR for this. Also, please do NOT create a PR until this issue has been assigned to you. Thank you @Roshansuthar1105 😊

[ArthSonani]

@Roshansuthar1105 could please assign this to me?

[nihams]

@ArthSonani i am asking for the issue to be assigned to me already :)

[Roshansuthar1105]

@nihams assigned.

[nihams]

@Roshansuthar1105 Could you provide access to the MongoDB Atlas user publicuser readWrite on the codify database. Currently, OAuth signup fails with: “user is not allowed to do action [insert] on [codify.users]” (Atlas code 8000).
Otherwise provide a separate connection user (username/password) that has readWrite on codify, or a different database name I can write to for local development.

[Roshansuthar1105]

@nihams use your own mongodb uri for locally to check and verify your changes.
If all works perfectly then make a pr.
Make sure to match the user model entries for both manually signup and using google signup.
Ask if you are having any doubts.