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>
```
from localstack.config import HOSTNAME, HOSTNAME_EXTERNAL
from localstack.utils import persistence
from localstack.utils.aws import aws_stack
from localstack.utils.common import (
    short_uid, timestamp, TIMESTAMP_FORMAT_MILLIS, to_str, to_bytes, clone, md5, get_service_protocol)
from localstack.utils.analytics import event_publisher
from localstack.utils.aws.aws_responses import requests_response
from localstack.services.s3 import multipart_content
from localstack.services.generic_proxy import ProxyListener
S3_NOTIFICATIONS = {}
BUCKET_CORS = {}
BUCKET_LIFECYCLE = {}
BUCKET_REPLICATIONS = {}
BUCKET_ENCRYPTIONS = {}
OBJECT_LOCK_CONFIGS = {}
LOGGER = logging.getLogger(__name__)
XMLNS_S3 = 'http://s3.amazonaws.com/doc/2006-03-01/'
BUCKET_NAME_REGEX = (r'(?=^.{3,63}$)(?!^(\d+\.)+\d+$)' +
    r'(^(([a-z0-9]|[a-z0-9][a-z0-9\-]*[a-z0-9])\.)*([a-z0-9]|[a-z0-9][a-z0-9\-]*[a-z0-9])$)')
NOTIFICATION_DESTINATION_TYPES = ('Queue', 'Topic', 'CloudFunction', 'LambdaFunction')
OBJECT_METADATA_KEY_PREFIX = 'x-amz-meta-'
ALLOWED_HEADER_OVERRIDES = {
    'response-content-type': 'Content-Type',
    'response-content-language': 'Content-Language',
    'response-expires': 'Expires',
    'response-cache-control': 'Cache-Control',
    'response-content-disposition': 'Content-Disposition',
    'response-content-encoding': 'Content-Encoding',
}
def event_type_matches(events, action, api_method):