#15 Add a very basic AuthToken class to provide auth tokens to API methods

GitHub: https://github.com/PramodKumarYadav/restpro Goal: - Show how to use Auth Tokens in API classes. This should be refactored later to make it production ready. Objective: - Add a very basic AuthToken class to provide auth tokens to API methods Next steps: - Refactor request headers to its own Base Request class.