tests/Utils.hs: add a version of retryT that returns the number of attempts
tests/Utils: change context of tryT to MonadBaseControl IO m
Test utils for DynamoDb
Minimal dynamoDb test suite

Currently only basic table creation, description, and deletion is covered.
tests/Utils.hs: add function 'mustFail'
tests/Sqs/Main.hs: add function SqsT to run requests with a given manager and base configuration
tests/DynamoDb/Utils.hs: add function dyT to run requests with a given manager and base configuration
tests/DynamoDb: add test case for reuse of TCP connections
tests/Sqs: add test case for reuse of TCP connections