Added Bubble Sort algorithm implementation in Solidity

[Akshat0125]

🧠 Description

This pull request adds the Bubble Sort algorithm implemented in Solidity.
It includes a simple contract example demonstrating sorting an array of integers.

🔨 Changes Made

• Added BubbleSort.sol in contracts/algorithms/
• Wrote comments explaining the logic
• Added a sample test in test/BubbleSortTest.sol
• Updated README with algorithm reference

✅ Testing

• Contract compiled successfully in Remix and Hardhat.
• Verified the output of the sorted array matches expectations.

[Akshat0125]

Hi! I’ve added the Bubble Sort algorithm in Solidity for Hacktoberfest.
Please review when you get a chance. Thank you!