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
```
LAMBDA_RUNTIMES = [LAMBDA_RUNTIME_PYTHON27, LAMBDA_RUNTIME_PYTHON36, LAMBDA_RUNTIME_PYTHON37,
    LAMBDA_RUNTIME_PYTHON38, LAMBDA_RUNTIME_DOTNETCORE2, LAMBDA_RUNTIME_DOTNETCORE21, LAMBDA_RUNTIME_DOTNETCORE31,
    LAMBDA_RUNTIME_NODEJS, LAMBDA_RUNTIME_NODEJS610, LAMBDA_RUNTIME_NODEJS810,
    LAMBDA_RUNTIME_JAVA8, LAMBDA_RUNTIME_JAVA11, LAMBDA_RUNTIME_RUBY, LAMBDA_RUNTIME_RUBY25]
DOTNET_LAMBDA_RUNTIMES = [LAMBDA_RUNTIME_DOTNETCORE2, LAMBDA_RUNTIME_DOTNETCORE21, LAMBDA_RUNTIME_DOTNETCORE31]
LAMBDA_DEFAULT_TIMEOUT = 3
LAMBDA_DEFAULT_HANDLER = 'handler.handler'
LAMBDA_DEFAULT_RUNTIME = LAMBDA_RUNTIME_PYTHON38
LAMBDA_DEFAULT_STARTING_POSITION = 'LATEST'
LAMBDA_ZIP_FILE_NAME = 'original_lambda_archive.zip'
LAMBDA_JAR_FILE_NAME = 'original_lambda_archive.jar'
INVALID_PARAMETER_VALUE_EXCEPTION = 'InvalidParameterValueException'
BATCH_SIZE_RANGES = {
    'kinesis': (100, 10000),
    'dynamodb': (100, 1000),
    'sqs': (10, 10)
}
app = Flask(APP_NAME)
arn_to_lambda = {}
event_source_mappings = []
LOG = logging.getLogger(__name__)
exec_mutex = threading.Semaphore(1)
DO_USE_DOCKER = None
JSON_START_CHAR_MAP = {
    list: ('[',),
    tuple: ('[',),
    dict: ('{',),
    str: ('"',),
    bytes: ('"',),
    bool: ('t', 'f'),