[keycloak-dev] auth spi docs/examples available in master

WRote about 15 pages of docs. Created an example under examples/providers/authenticator. It is both a required action and authenticator example. If you have time, please review. If you don't...oh well... Refactored the SPI a bit when I created the examples. Hopefully it is a lot simpler. -- Bill Burke JBoss, a division of Red Hat http://bill.burkecentral.com