Launch WebUI (and do nothing else)

I would like to be able to run scalene on my code, but analyze the resulting json file at a later time and/or on a separate computer. A simple CLI way to simply launch the browser with scalene-gui/index.html would be useful.

Also, it isn't obvious that the web server was ephemeral. I spent a bit of time trying to figure out why port forwarding wasn't working before I dug in the code a bit. Perhaps as a temporary workaround, document that one can simply open the scalene-gui/index.html file in the browser, and everything runs fine.

Not all users are able to access external websites (or "upload" logs, as is suggested in the current documentation – though this appears to be a misnomer, and looks to me like its done entirely locally in JS).