Add Kinesis Firehose adapter and tests

[joemeehan]

Adding an adapter to send messages to a Kinesis Firehose stream. This adapter only supports the enqueue function (as that's the only thing you can do to a Kinesis Firehose delivery stream).

[biggianteye]

Consider using __FUNCTION__ in all the MethodNotSupportedException calls.

[wpillar]

Is kinesis firehose a queue?

[wpillar]

The fact that we're having to implement AdapterInterface with mostly MethodNotSupported implementations should be a flag, no? It looks like we're using this abstraction to simply wrap FirehoseClient not because it's a useful abstraction?

Fair/unfair?

[joemeehan]

I'd argue Firehose is a queue application, it's just that it handles consuming messages itself (into S3 or Redshift). In one of our other applications, we would be using it in a functionally equivalent way to the SqsAdapter (which is what we're doing at the moment) - having this alternative available would be useful.