feat: transaction proposal and execution mechanism

[emmanuelJet]

Feature Description

Develop the mechanism for proposing, approving, and executing transactions, including asset transfers and administrative changes that require multi-signature approval.

Acceptance Criteria

• Signers can propose transactions specifying recipient, amount, and data payload if needed.
• Transactions are assigned unique identifiers for tracking.
• Signers can approve and revoke approvals for proposed transactions.
• Transactions can be executed once the required number of approvals is met and the transaction timelock has elapsed.
• Transactions cannot be executed more than once.
• Transactions cannot proceed if total signers are less than the required threshold.