[keycloak-dev] logout by redirect

* Adding a flag to ClientModel "backchannelLogout" * Adding a method to LoginProtocol "Response redirectLogout(UserSessionModel, ClientSessionModel)" * Adding a flag to ClientSessionModel "loggedOut" ... or ... rename the Action attribute to State and add a "LOGGED_OUT" state. * Adding a redirectLogout REST endpoint for OIDC. * Adding a redirectLogout REST endpoint for adapters. Algorithm will be: 1. do all backchannel logouts 2. Find a logged in client 3. Redirect based on protocol 4. Receive logout success from a redirection, goto 2 -- Bill Burke JBoss, a division of Red Hat http://bill.burkecentral.com