WebAdapter: add getConnection method

[Naktibalda]

Direct access to WebSocket connection can be useful, but there were no means to access connection of specific user.

What I actually wanted to do:

I got a feature request to log user's ip and user agent, but they are only available in on connection event handler as a second parameter, so I implemented event handler and made it assign custom properties to WebSocket objects.

if (controller.adapter instanceof WebAdapter) {
    controller.ready(() => {
        const wsServer: WebSocket.Server = controller.adapter.wss;
        wsServer.on('connection', (ws, req) => {
            ws.ip = req.connection.remoteAddress;
            ws.userAgent = req.headers['user-agent'];
        });
    });
}

Then I can access them in my bot's code like this:

if (bot.controller.adapter instanceof WebAdapter) {
	const connection = bot.controller.adapter.getConnection(message.user);
	console.log(connection.ip);
	console.log(connection.userAgent);
}