feat: executor role functionality

[emmanuelJet]

Feature Description

Develop the Executor role with specific permissions, including initiating owner override functions with timelocks and overriding pending transactions under specified conditions.

Acceptance Criteria

• Executor can initiate an owner override function that is delayed by the owner override timelock.
• Signers can sign the owner override only after the owner override timelock has elapsed.
• Executor can override a pending transaction when signers have not signed within the required time frame, under the specified conditions.
• All Executor functions are thoroughly unit-tested.