Update to get dynamically api port for websocket

[BZHunt]

fix #411

[BorysekOndrej]

Hi, I've tried your PR and it's a very useful feature. Right now you have a typo here - the colon the before port number is duplicated, if the port is non default, e.g. https://localhost::8443

Either the library or browser then strips the ::8443 and tries it on default port (443 for https).

Suggested change

	var socket = io(`${window.location.protocol}//${window.location.hostname}:${window.location.port != '' ? ':'+window.location.port : ''}`);
	var socket = io(`${window.location.protocol}//${window.location.hostname}${window.location.port != '' ? ':'+window.location.port : ''}`);

After this fix it looks good to me. It works even when the docker-compose port mapping is used, e.g.

  pwndoc-frontend:
    ports:
      - 8444:8443

👍