Fail on bad message

[kylepolich]

Enhance the function from #2 to throw a 500 error in cases where the message sent cannot be placed on the SNS queue.

• I don't know all the bad cases, so take some time to consider it yourself.
• SNS has max length, so fail with 500 and appropriate error message if the submission is too long
• If the request-body sent is not JSON, throw an exception