Add 307 redirect to AuthorizationListener

[oliverhausler]

Use case:

For building a server cluster, we wanted to 307 redirect to another machine before authentication occurs. I added an @Override isRedirected() to AuthorizationListener for this. I tried to make the change without breaking compatibility.

If it interests you, feel free to merge. If there's a better way to achieve this, please let me know.

I based the change on 1.7.13 because it's the latest stable version.

[oliverhausler]

I have also written an improved AuthorizationListener at https://github.com/oliverhausler/netty-socketio/tree/1.7.13-improved-authorization

public class CustomAuthorizationListener implements AuthorizationListener {

    @Override
    public AuthorizationResponse authorize(HandshakeData data) {
        return AuthorizationResponse.connect("key", "value"); // adds initial data to the store

        // Alternatives:
        // return AuthorizationResponse.disconnect(); // disconnects with 401 Unauthorized
        // return AuthorizationResponse.redirect("https://") // returns a redirect URL to the client
    }

}

Data can then be retrieved as `client.get("key");

untested, undocumented

[mrniko]

It's a bad practice to swallow Exceptions. Please fix

[oliverhausler]

I'm not working on this PR branch anymore. I decided to carefully break compatibility in some places to implement more features, see #631 instead, where this is fixed.

Instead returning isRedirected in a separate @OverRide, I decided to move it into the same authorize function and return a response object instead a boolean. This breaks compatibility, but enables us to do a lot more.

I'd suggest you reject this PR and switch to the newer one.

[oliverhausler]

8fb13b0