feat: access control using openzeppelin

[emmanuelJet]

Feature Description

Utilize OpenZeppelin's AccessControl library to manage roles and permissions in the contract, ensuring standardized and secure access control mechanisms.

Acceptance Criteria

• Roles are defined using AccessControl (Owner, Executor, Signer).
• Role-based permissions are implemented correctly.
• Role administration is managed securely.
• Role assignments and revocations are handled appropriately.
• Appropriate events are emitted for role changes.