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
```
is_java = lambda_executors.is_java_lambda(runtime)
    if is_java:
        
        
        
        lambda_handler = get_java_handler(zip_file_content, tmp_file, func_details=lambda_details)
    if not is_local_mount:
        
        if not is_zip_file(zip_file_content):
            raise ClientError(
                'Uploaded Lambda code for runtime ({}) is not in Zip format'.format(runtime))
        
        if not is_java or zip_contains_jar_entries(zip_file_content, 'lib/'):
            unzip(tmp_file, lambda_cwd)
    
    if not is_java:
        handler_file = get_handler_file_from_name(handler_name, runtime=runtime)
        handler_function = get_handler_function_from_name(handler_name, runtime=runtime)
        main_file = '%s/%s' % (lambda_cwd, handler_file)
        if not os.path.exists(main_file):
            
            
            
            if not is_local_mount or not use_docker() or config.LAMBDA_REMOTE_DOCKER:
                file_list = run('cd "%s"; du -d 3 .' % lambda_cwd)
                config_debug = ('Config for local mount, docker, remote: "%s", "%s", "%s"' %
                    (is_local_mount, use_docker(), config.LAMBDA_REMOTE_DOCKER))
                LOG.debug('Lambda archive content:\n%s' % file_list)
                raise ClientError(error_response(
                    'Unable to find handler script (%s) in Lambda archive. %s' % (main_file, config_debug),