[Feature] <Added Sales Tax Calculator>

[AshmitZaware1234]

Description

This project is a web-based sales tax calculator that allows users to compute the gross amount and tax amount based on the net price and tax rate, or to determine the tax rate based on the net and gross amounts. It also includes a pop-up information window as a user guide.

Screenshots

No response

Checklist

• [X] I have checked the existing issues.
• [X] I follow Contributing Guidelines of this project.
• [X] I am a GSSOC'24 contributor.
• [ ] I am a IWOC'24 contributor.
• [ ] I am a JWOC'24 contributor.
• [ ] I am a SWOC'24 contributor.

Code of Conduct

• [X] I agree to follow this project's "Code of Conduct".

[AshmitZaware1234]

Please assign me this issue