Update smart contracts folder structure

[VGau]

Description

Reorganize the folder structure of the smart contracts to improve clarity, maintainability, and scalability. This includes categorizing contracts into subfolders based on functionality (e.g., tokens, utils, governance) and updating references in all related files and scripts.

Motivation

A more intuitive folder structure enhances developer productivity, reduces onboarding time for new team members.

Tasks

• Create subfolders for smart contracts based on functionality (tokens, governance, utils, etc.).
• Update all imports and references in contracts, related scripts and configuration files.
• Verify deployment scripts and test cases work with the new structure.
• Document the new folder structure in the development guide.

Acceptance criteria

• All smart contracts are organized into appropriate subfolders.
• All references, imports, and scripts are updated to reflect the new structure.
• Deployment scripts execute without errors.
• All tests pass successfully with the new structure.
• Documentation is updated to reflect the new folder structure.

Risks

• Risk of broken imports or references in contracts, scripts and tests.