As an enhancement to https://github.com/localstack/localstack/pull/1194

It would be really helpful to send the Lambda name, either as data, a header, or as part of the URL.

At code location: https://github.com/localstack/localstack/blob/03c6f4bf250edd18eb818ed65090f508636b0bff/localstack/services/awslambda/lambda_api.py#L696

I can likely open a PR to handle this given some feedback on the feature and potential design.

Right now all I see is the following (using `npx http-echo-server`):
```
[socket#8] event: data
--> POST / HTTP/1.1
--> Host: 192.168.1.x:3000
--> User-Agent: python-requests/2.22.0
--> Accept-Encoding: gzip, deflate
--> Accept: */*
--> Connection: keep-alive
--> Content-Length: 9
--> Content-Type: application/x-www-form-urlencoded
-->
-->
[socket#8] event: data
--> Name=test
```
)
                        messages = result.get('Messages')
                        if not messages:
                            continue
                        send_event_to_lambda(queue_arn, queue_url, lambda_arn, messages, region=region_name)
                    except Exception as e:
                        LOG.debug('Unable to poll SQS messages for queue %s: %s' % (queue_arn, e))
            except Exception:
                pass
            finally:
                time.sleep(SQS_POLL_INTERVAL_SEC)
    LOG.debug('Starting SQS message polling thread for Lambda API')
    SQS_LISTENER_THREAD['_thread_'] = FuncThread(listener_loop)
    SQS_LISTENER_THREAD['_thread_'].start()
def process_sqs_message(queue_name, region_name=None):
    
    try:
        region_name = region_name or aws_stack.get_region()
        queue_arn = aws_stack.sqs_queue_arn(queue_name, region_name=region_name)
        sources = get_event_sources(source_arn=queue_arn)
        arns = [s.get('FunctionArn') for s in sources]
        LOG.debug('Found %s source mappings for event from SQS queue %s: %s' % (len(arns), queue_arn, arns))
        source = (sources or [None])[0]
        if not source:
            return False
        start_lambda_sqs_listener()
        return True
    except Exception as e:
        LOG.warning('Unable to run Lambda function on SQS messages: %s %s' % (e, traceback.format_exc()))
def get_event_sources(func_name=None, source_arn=None):