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
```
if runtime.startswith(LAMBDA_RUNTIME_PROVIDED):
        return 'bootstrap'
    delimiter = '.'
    if runtime.startswith(LAMBDA_RUNTIME_NODEJS):
        file_ext = '.js'
    elif runtime.startswith(LAMBDA_RUNTIME_GOLANG):
        file_ext = ''
    elif runtime.startswith(tuple(DOTNET_LAMBDA_RUNTIMES)):
        file_ext = '.dll'
        delimiter = ':'
    elif runtime.startswith(LAMBDA_RUNTIME_RUBY):
        file_ext = '.rb'
    else:
        handler_name = handler_name.rpartition(delimiter)[0].replace(delimiter, os.path.sep)
        file_ext = '.py'
    return '%s%s' % (handler_name.split(delimiter)[0], file_ext)
def get_handler_function_from_name(handler_name, runtime=LAMBDA_DEFAULT_RUNTIME):
    
    if runtime.startswith(tuple(DOTNET_LAMBDA_RUNTIMES)):
        return handler_name.split(':')[-1]
    else:
        return handler_name.split('.')[-1]
def error_response(msg, code=500, error_type='InternalFailure'):
    LOG.warning(msg)
    return aws_responses.flask_error_response(msg, code=code, error_type=error_type)
def get_zip_bytes(function_code):
    """Returns the ZIP file contents from a FunctionCode dict.
    :type function_code: dict