Feat: Implement entry and tax functionality and modularized codebase

[DMZTdhruv]

Pull Request Summary

This pull request implements several key updates and improvements across the codebase, particularly in entry and tax functionalities, as well as some UI and code structure enhancements.

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Entry Functionality

• Added a button to enable users to add new entries.
• Implemented edit functionality for entry details, allowing users to modify entry-specific information.
• Enhanced the total summation for entries, ensuring accurate and correct calculations.

Tax Management

• Enabled functionality to add and edit tax values.
• Improved tax summation calculations, now correctly summing based on the tax values provided.

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Navbar Update

• Removed the "Get Invoice" option from the navbar when on the Generate page to streamline the user experience.

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Code Refactoring

• Refactored the entire codebase to improve readability, maintainability, and performance.

[DMZTdhruv]

resolved #13 @aayushchugh please review it