[keycloak-dev] LDAP integration

For the first round of LDAP integration we will only focus on authenticating with LDAP. This will work by adding an Authentication SPI. It will provide two methods, verify user password and update user password. We'll have two implementations of this, Keycloak Model and LDAP (via PicketLink). It should be possible to configure which Authentication SPI provider is used by a Realm through the admin console. This will include setting up configuration for the LDAP server. Second round (which will have a low priority for beta1, so will most likely be postponed to after the 1.0.Final) will be to add a Sync SPI. This will support one-way and two-way of syncing data from an external resource into the Keycloak model. It will support resource that allows registering listeners for events (for near real-time syncing) as well as interval based pulling when this is not possible. JIRA issue for this is: https://issues.jboss.org/browse/KEYCLOAK-316