Upgrade of SPS Contract to SPSv2

[patrickgorrell]

Pull Request: Upgrade of SPS Contract to SPSv2

Summary

This pull request introduces a significant upgrade from the original SPS contract to the new SPSv2 version. The update encompasses enhancements in security, functionality, and efficiency, reflecting best practices and addressing the evolving needs of our platform and its users.

Key Upgrades

Enhanced Security with ReentrancyGuard

• Original Contract: Lacked explicit protection against reentrancy attacks.
• SPSv2: Integrates OpenZeppelin's ReentrancyGuard to secure all state-changing functions against reentrancy, providing an additional layer of security.

Role-Based Access Control Improvements

• Original Contract: Utilized basic ADMIN_ROLE and MINTER_ROLE management.
• SPSv2: Refines role management with clearer, more granular control. It introduces functions for explicitly granting and revoking these roles, making role management more intuitive and flexible.

Voting and Delegation Mechanism

• Original Contract: Included a basic framework for delegation.
• SPSv2: Enhances the delegation system with EIP-712 compliance, enabling secure, gasless transactions through signature-based delegation. This upgrade simplifies the user experience while maintaining security and trust.

Removal of Redundant SafeMath

• Original Contract: Relied on SafeMath for all arithmetic operations, a necessity prior to Solidity ^0.8.0.
• SPSv2: Leverages Solidity ^0.8.0's built-in overflow and underflow checks, removing the need for SafeMath and optimizing contract efficiency.

Deployment and Testing

A deployment script has been introduced and reflects the new SPSv2 contract structure. Comprehensive testing has been conducted to ensure backward compatibility where feasible and to validate the new functionalities and security measures.