[keycloak-dev] Registration flow, Form SPI, and Recaptcha Support

Added registration flow. As part of this a new Form SPI was created. This Form SPI should only be used when you have a form that has optional parts. For example, a form might have password and otp on it, but you don't want to process otp unless it is enabled. The registration flow now has a Recaptcha option that is disabled by default. I don't know why, but I had trouble getting this to work all the time on Firefox. To enable Recaptcha you do have to muck with our Security Defenses headers i.e. Content-Security-Policy. All this is documented in docbook. -- Bill Burke JBoss, a division of Red Hat http://bill.burkecentral.com