Add a authorizer function for the API Gateway (Websocket) endpoint

By default the websocket is open for anyone to connect too.

Think it would be better practice if there was a basic lambda that maybe could verify a token of some sort? Like the example seen here https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-lambda-authorizer.html

```js
exports.handler = async(event) => {
let response = {
"isAuthorized": false,
"context": {
"stringKey": "value",
"numberKey": 1,
"booleanKey": true,
"arrayKey": ["value1", "value2"],
"mapKey": {"value1": "value2"}
}
};

if (event.headers.authorization === "secretToken") {
response = {
"isAuthorized": true,
"context": {
"stringKey": "value",
"numberKey": 1,
"booleanKey": true,
"arrayKey": ["value1", "value2"],
"mapKey": {"value1": "value2"}
}
};
}

return response;

};
```

Maybe the websocket could send a authorization header, then we could allow the connection if it matches....

Start with the API Gateway WebSocket endpoint and the linked AWS Lambda authorizer example. Determine how this construct configures connection authorization and define which token or authorization header should be accepted; done means unauthorised connections are rejected while valid ones are allowed.

Written by the indexing model from the issue text.