SNS event's new SqsSubscription option does not follow recommended configuration

[ljacobsson]

When setting SqsSubscription: true on an SNS event, SAM will put a queue without any properties set in front of the lambda function.

According to AWS docs, the VisibilityTimeout should be set to give lambda's retry logic a chance to retry twice before the message becomes available:

https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html

To allow your function time to process each batch of records, set the source queue's visibility timeout to at least 6 times the timeout that you configure on your function. The extra time allows for Lambda to retry if your function execution is throttled while your function is processing a previous batch.

Would also be nice if there were optional properties to build a redrivePolicy and a DLQ so messages don't retry relentlessly for 4 days.

[jlhood]

@ljacobsson Thanks for bringing this up. The current SqsSubscription: true feature was part of the solution proposed in #854. There is additional work to do to support further configuration of SQS, but it should be tracked under that issue. You bring up a good point though that SAM should allow use cases where more advanced SQS queue configuration is needed. I'll update #854 with this additional requirement.