Add Contract Verification Feature and Update Testnet to Sepolia

[codeesura]

This PR introduces significant enhancements to the project, primarily focusing on the deployment and verification of contracts on both the Scroll mainnet and testnet. Below are the key changes and their implications:

1. Contract Verification Feature:

• Implemented a new feature that enables automatic contract verification post-deployment on both the Scroll mainnet and testnet.
• This feature enhances transparency and trustworthiness by allowing users and developers to verify the source code on the blockchain explorer directly.
• Added necessary scripts and configurations to support this functionality, including modifications in the deployment script to automatically trigger the verification process using Hardhat's Etherscan plugin.

2. Testnet Transition from Alpha to Sepolia:

• Updated the project's testnet configuration from the Alpha testnet to the Sepolia testnet.
• Adjusted network configurations and URLs in the Hardhat setup to reflect this transition, ensuring compatibility and seamless integration.

3. Distinct Configurations for Mainnet and Testnet:

• Introduced separate configurations for the Scroll mainnet and testnet in the Hardhat setup.
• This distinction allows for more precise and targeted deployments, catering to the specific needs and characteristics of each network.
• The update includes distinct API endpoints and parameters for each network, enhancing the deployment and verification process's efficiency and accuracy.