Account settings are stored using the WebID as key.
Reason for using the WebID is that this allows faster access to the settings
in authenticated requests.
A consequence of this is that passwords are now always required during registration,
and that there can only be 1 account per WebID.
This adds options for enabling setup to the config folder.
All default configs with permanent storage (file/sparql)
are configured to require setup at server start.
Memory-based configs merely have it as an option.
The IDP behaviour has been changed to move all error related knowledge
to the IdentityProviderHttpHandler instead of managing it
in the Interactionhandlers.
