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
```
self.s3_client.upload_fileobj(
            BytesIO(zip_file), bucket_name, bucket_key)
        
        response = self.lambda_client.create_function(
            FunctionName=lambda_name, Handler='handler.handler',
            Runtime=lambda_api.LAMBDA_RUNTIME_PYTHON27, Role='r1',
            Code={
                'S3Bucket': bucket_name,
                'S3Key': bucket_key
            },
            Publish=True
        )
        self.assertIn('Version', response)
        
        data_before = b'{"foo": "bar with \'quotes\\""}'
        result = self.lambda_client.invoke(
            FunctionName=lambda_name,
            Payload=data_before,
            Qualifier=response['Version']
        )
        data_after = json.loads(result['Payload'].read())
        self.assertEqual(json.loads(to_str(data_before)), data_after['event'])
        context = data_after['context']
        self.assertEqual(response['Version'], context['function_version'])
        self.assertEqual(lambda_name, context['function_name'])
        
        expected = ['Lambda log message - print function']
        if use_docker():