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
```
'payload': {'S': str(data)}
        }
        aws_stack.create_dynamodb_table(table_name, partition_key='id')
        dynamodb.put_item(TableName=table_name, Item=item)
        return ''
    if re.match(r'^https?://.+', config.LAMBDA_FALLBACK_URL):
        response = safe_requests.post(config.LAMBDA_FALLBACK_URL, data)
        return response.content
    raise ClientError('Unexpected value for LAMBDA_FALLBACK_URL: %s' % config.LAMBDA_FALLBACK_URL)
def get_lambda_policy(function):
    iam_client = aws_stack.connect_to_service('iam')
    policies = iam_client.list_policies(Scope='Local', MaxItems=500)['Policies']
    docs = []
    for p in policies:
        
        versions = iam_client.list_policy_versions(PolicyArn=p['Arn'])['Versions']
        default_version = [v for v in versions if v.get('IsDefaultVersion')]
        versions = default_version or versions
        doc = versions[0]['Document']
        doc = doc if isinstance(doc, dict) else json.loads(doc)
        if not isinstance(doc['Statement'], list):
            doc['Statement'] = [doc['Statement']]
        for stmt in doc['Statement']:
            stmt['Principal'] = stmt.get('Principal') or {'AWS': TEST_AWS_ACCOUNT_ID}
        doc['PolicyArn'] = p['Arn']
        doc['Id'] = 'default'
        docs.append(doc)
    policy = [d for d in docs if d['Statement'][0]['Resource'] == func_arn(function)]
    return (policy or [None])[0]
def not_found_error(ref=None, msg=None):