Consider disabling user registration by default

[pameeela]

Got to thinking when testing #86, should we modify the default user settings in Starshot to disable user registration? Certainly in my experience, it is rarely needed, and far more often I find sites where it isn't needed but no one knew to turn it off so they get filled with spam accounts.

Wondering what others thing? I'm not saying that user registration isn't needed, just that I think it's better as opt-in than opt-out.