Implement fault tolerance mechanisms (e.g., retries, dead-letter queues, circuit breakers) E5.

[chendiblessing]

Description:
Develop and implement mechanisms to enhance the fault tolerance of the DIDComm mediator server. This includes integrating retry logic for failed operations, setting up dead-letter queues for undeliverable messages, and using circuit breakers to prevent cascading failures. The goal is to ensure that the server can continue to operate under adverse conditions or gracefully handle failures.

Acceptance Criteria:

• Implemented retry mechanisms for key operations.
• Configured dead-letter queues for handling undeliverable messages.
• Integrated circuit breaker pattern to manage failing components.