As a logged in user, I want be able to create a gamelobby, for other players to join.

Development Tasks:

As a logged in user:

[x] I want to click on a 'create' button to create a new lobby.
[x] I want to be redirected into my own lobby.
[x] I want to be able to switch between a public and private lobby by clicking a button.
[x] In a private lobby I want to have a passcode which I can share with friends, so they can join my lobby.
[x] In a public lobby I want other people to be able to join without any extra steps.