**Overview**

In AWS it is possible to trigger step functions through an API Gateway integration, see https://docs.aws.amazon.com/step-functions/latest/dg/tutorial-api-gateway.html

Similar integrations already occur within localstack, however the step function URIs are notably missing. See lines 66-88 of https://github.com/localstack/localstack/blob/master/localstack/services/apigateway/apigateway_listener.py



┆Issue is synchronized with this [Jira Bug](https://localstack.atlassian.net/browse/LOC-107) by [Unito](https://www.unito.io/learn-more)

response_templates = {'application/json': json.dumps({'TableName': 'MusicCollection',
                                                              'Item': {'id': '$.Id', 'data': '$.data'}})}
        api_id = self.create_api_gateway_and_deploy(response_templates, True)
        url = gateway_request_url(api_id=api_id, stage_name='staging', path='/')
        payload = {
            'name': 'TEST-PLAN-2',
            'description': 'Description',
            'quota': {'limit': 10, 'period': 'DAY', 'offset': 0},
            'throttle': {'rateLimit': 2, 'burstLimit': 1},
            'apiStages': [{'apiId': api_id, 'stage': 'staging'}],
            'tags': {'tag_key': 'tag_value'},
        }
        client = aws_stack.connect_to_service('apigateway')
        usage_plan_id = client.create_usage_plan(**payload)['id']
        key_name = 'testApiKey'
        key_type = 'API_KEY'
        api_key = client.create_api_key(name=key_name)
        payload = {'usagePlanId': usage_plan_id, 'keyId': api_key['id'], 'keyType': key_type}
        client.create_usage_plan_key(**payload)
        response = requests.put(
            url,