Refactor: Google auth implementation to use RSA keys

[VaibhavSingh8]

Issue Description

• The HS256 algorithm with symmetric key is being used for signing tokens instead of the RS256 algorithm with public and private keys.
• Since the frontend was not integrated, an alternative method for testing the logic was implemented to return HTML content for testing purposes.

Expected Behaviour

• RSA public and private keys should be used for encoding and decoding the auth token.
• The callback implementation should redirect to the frontend URL instead of returning HTML.

Severity/Priority

• Critical
• High
• Medium
• Low

Additional Information

N/A

Checklist

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.

[VaibhavSingh8]

Closed via #102