Fixes #3829: allow LDAP authentication mixed with rudder-users.xml defined authorizations

The main idea of that pull request is to provide to Spring LDAP authenticator an different implementation for the part that get User Details, and in particular the "rights" part. It's the goal of "rudderXMLUserDetails" bean. 

To try that, you will have to change authroization declaration as explained in the Rudder documentation, updated with what is in https://github.com/Normation/rudder-doc/pull/21