add(sudoku.go): implement SolveSudoku with optimized backtracking

[bensaine]

Pull Request: Implement SolveSudoku Function with Optimized Backtracking

Overview

This pull request adds the SolveSudoku function to solve a Sudoku grid efficiently using backtracking. Additionally, the implementation incorporates techniques such as naked singles and hidden singles to reduce the number of recursive calls, improving overall performance.

Changes Made

• Implemented the SolveSudoku function in sudoku.go.
• Utilized backtracking to explore possible solutions and backtrack when necessary.
• Integrated naked singles and hidden singles calculations to optimize the solving process, and reduce the number of recursive steps needed. This drastically improves performance, especially for easy puzzles.
• Added relevant comments for clarity.