Update Configuration, Static Files Location, and Add Receipt Feature

[radinceorc]

Summary of Changes:

1. Configuration Updates:

   • Added the pyproject.toml and updated the pre-commit configuration for better code quality and consistency.

2. Package and Documentation Updates:

   • Updated Python packages to the latest versions.
   • Revised the README.md to reflect the changes in configurations and package updates.

3. Static Files Management:

   • Moved static files to be stored within each app's static folder for better modularity and organization.
   • Adjusted the settings.py to ensure Django finds and serves static files correctly.

4. New Feature: Receipt

   • Added a new feature named Receipt to the application.
   • Updated the Invoice model and admin interface to support the receipt feature.
   • Adjusted related templates, forms, and views to handle the receipt functionality.

5. Model and Admin Changes:

   • Updated models to accommodate the receipt feature.
   • Modified the admin interface to enhance the management of invoices and receipts.
   • Added necessary validations and constraints to the model.

6. Other Adjustments:

   • Refactored various parts of the codebase to improve maintainability and adhere to the updated configuration.
   • Ensured compatibility with the new setup and fixed any related issues.