Adding some important feature

1. Added streaming feature of ollama for llama3 model.
2. hashing passwords
3. added spring security
4. displays the message if passwords do not match the set criteria on the signup page and if the email is already registered
5. if the password or email is wrong, add error messages to the login page.
6. handled exceptions
7. adding javascript files to show the response from the llama3 model dynamically and removing the loading screen.