2-Factor-authentication feature

Hi!

I think it might be a really good idea to add an optional 2-factor authentication to minecraft logins. These should then be required to log in inside the launcher and on the web page.

2-factor authentication can provide much better security for user.

I am unsure whether to post it here or on the WEB category, it would be nice if you could move it if you think it belongs to the WEB category; essentially its a request for both platforms.