Integrate User Login System with Database Management

[berry1104]

Description: Previously, we have successfully implemented the user login form and the integration with a database using Flask-SQLAlchemy. The next step is to combine these features to enhance the user login system.

• [x] Password Hashing: Implement password hashing for secure storage in the database.
• [x] Logging Users In: Set up the login functionality that verifies usernames and hashed passwords.
• [x] Logging Users Out: Develop a logout mechanism that ends the user's session.
• [x] Requiring Users to Login: Establish a system to ensure certain pages require user login. The specifics will be adjusted based on future features integration.
• [x] User Registration: Create a registration form that includes error handling for existing usernames and password strength validation.

[berry1104]

create new branch 11-integrate-user-login-system-with-database

[berry1104]

for now, only add @login_required under "world map" page