Remove SqsPolicy from JustSaying

[Quazimon]

I found that during the subscription creation we're rewritting Policy attribute. And this one is done in a very strict maner - all existing policy statements are being deleted. See usage here and implementation here.

The main thing is that we don't need this operation at all because inside IAmazonSimpleNotificationService.SubscribeQueueAsync is well implemented policy updater that will keep existing statements & add new based on the TopicArn. See the link to AWS SDK.

Suggested solution: remove custom policy updater from JustSaying because

1. it's an unnecessary API call
2. we don't want to override existing statements inside policy

Possible solution: allow JustSaying to set their custom policy over policy that is created via AWS SDK (but not override it)