Improving the token.js file by Improving Token Handling and Security

[RishiVT2004]

Issue

The current implementation of the token.js file for handling JWT tokens and faculty registration tokens can be enhanced to improve maintainability, security, and error handling. The current approach lacks proper error messages, environment variable validations, and flexibility in token expiration management.

Proposed Changes :

1. Adding Async Functionality to code
2. Enhancing Error Handling
3. Setting Dynamic Token Expiration and Environment Variable Validation

@Harshdev098 please assign this issue to me and add gssoc-ext and hacktoberfest tags in it