v0.4.1

1. Refactored code base
2. Introduced experimental_guest_login feature enabling users to login via OAuth2 with Google and Microsoft 🚀 NEW
3. Added single_session parameter to login and experimental_guest_login widgets to limit each individual user to a one session
4. Removed pre_authorized list from Authenticate class and added it directly to register_user widget
5. Added merge_username_email parameter to register_user widget to combine username into email field
6. Added roles field to user credentials
7. Added password hint parameter/field to register_user widget and credentials
8. Added password_instructions parameter to Authenticate class to provide password requirements instructions to register_user and reset_password widgets
9. Added option to provide config file path to Authenticate class as a single parameter instead of providing the credentials, cookie name, cookie key, cookie expiry days, and pre_authorized as separate parameters to the Authenticate class. This eliminates the need to read/update the config file separately, instead, Streamlit-Authenticator will automatically read/update the config file for all operations.
10. Fixed Validator parameter bug in Authenticate class
11. Addressed double login bug
12. Addressed auto_hash parameter bug in Authenticate class