Calculate currency logic updated and modified

[Amarok121]

What

This PR adds the login functionality for users. It includes the following changes:

• Implemented level parameter usage to calculateCurrency method, and to the correspoding part in Core.java.
• Also modified hitrate, to change the amount of reward along to it.

Why

The new parameter and logic modification is for improving the currency function to be more diverse and balanced.

Related Issue

Closes #123

How to Test

1. Start the application locally.
2. Navigate to the login page and try logging in with a valid account. Ensure the session is established.
3. Try logging in with invalid credentials and check if appropriate error messages are displayed.

Screenshots

Additional Information

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