feat: authentication module that supports both OAuth2

[srijan-chaudhuri]

Description of Change:

This PR introduces a cleaner way of handling errors so users can get more information about the point of failure.

Key changes:

OAuth2 authentication using client_id, client_secret, and refresh_token.
Password-based authentication using username, password, and security_token.
Retry logic for OAuth2 failures via the backoff library, ensuring retriable errors like expired tokens are automatically handled.
Automatic token refresh every 15 minutes using a background thread for OAuth2.
Config parsing to select and use the correct credential type (OAuth or password).

Closes issue:

#62