Added handling of 'private' param to http events.

[vonpoland]

Description

Adding private:true to state machine events

"events": [
      {
        "http": {
          "path": "delijn/bookings/callback",
          "method": "post",
          "private": true
        }
      }
    ]

Should set ApiKeyRequired: true in AWS::ApiGateway::Method template.
https://docs.aws.amazon.com/apigateway/latest/developerguide/api-gateway-setup-api-key-with-restapi.html

Without this parameter x-api-keys are ignored.

Fix description

private:true is now handled and used in AWS::ApiGateway::Method.

[horike37]

Awesome @vonpoland 👍
Thanks 😄