Separate Keygen Cloud and Keygen EE multiplayer mode

[ezekg]

I've had some interest in the multiplayer mode of Keygen EE. Let's separate out Keygen Cloud and Keygen EE a bit more, e.g. Stripe and email reports are only needed for Keygen Cloud. Maybe add something like the following?

module Keygen
  def cloud?   = ee { _1.entitled?(:cloud) }
  def cloud(&) = yield if cloud?
end

[ezekg]

Some things to note:

• New accounts for EE need billing initialized, but not Stripe.
• Add a way to disable new account creation for EE.