The form POST operation to S3 accepts a `success_action_status` field which can be set to 200/201/204, see [here](https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectPOST.html). Localstack currently handles the `success_action_redirect` field [here](https://github.com/localstack/localstack/blob/master/localstack/services/s3/s3_listener.py#L518) and so we should look into handling the `success_action_status` field too.

The 201 from AWS responds with an XML document with some fields about the object that has just been created in AWS, see below.

```
<PostResponse>
    <Location>https://s3.amazonaws.com/link-to-the-file</Location>
    <Bucket>s3-bucket</Bucket>
    <Key>development/8614bd40-691b-4668-9241-3b342c6cf429/image.jpg</Key>
    <ETag>"32-bit-tag"</ETag>
</PostResponse>
```
'x-amz-id-2': 'eftixk72aD6Ap51TnqcoF8eFidJG9Z/2'  
            },
            's3': {
                's3SchemaVersion': '1.0',
                'configurationId': 'testConfigRule',
                'bucket': {
                    'name': bucket_name,
                    'ownerIdentity': {
                        'principalId': 'A3NL1KOZZKExample'
                    },
                    'arn': 'arn:aws:s3:::%s' % bucket_name
                },
                'object': {
                    'key': file_name,
                    'size': file_size,
                    'eTag': 'd41d8cd98f00b204e9800998ecf8427e',
                    'versionId': version_id,
                    'sequencer': '0055AED6DCD90281E5'
                }
            }
        }]
    }
def queue_url_for_arn(queue_arn):
    if '://' in queue_arn:
        return queue_arn
    sqs_client = aws_stack.connect_to_service('sqs')
    parts = queue_arn.split(':')
    return sqs_client.get_queue_url(QueueName=parts[5],
        QueueOwnerAWSAccountId=parts[4])['QueueUrl']
def send_notifications(method, bucket_name, object_path, version_id):