Add support for Job retries

[rodber]

Add methods withMaxRetries(int $maxRetries) and maxRetries(): int. Default 0.

Enable to re-run a work (n) times. Indicate how many times it failed and store each throwable.

Add methods withRetryDelay(int $seconds) and retryDelay(): int.

If a Job fail, retry after the delay (linear or expo) until reaching max retries.