Improvements for setup and login

Small improvements:

• Hide google/facebook button if it isn't configured (which is normal for non-production instance)
• Clean up promises for properly setup correct system preference
• Update tests for rely only on configurator to setup the instance**

There still hateoas_url and authentication policy that are later set. But this configuration is expected (like MailHost) since it depends on the site infrastructure and who is setuping it.