Adapt LDAP for auto/manual generated id. name, add unit tests for
special workflow (user which are created without authentication and get
LDAP token afterwards on login)

Login happens only with authentication informations, identity name is
now only used for legacy directory name. User name of authentication can
be changed. LDAP users can be imported with LDAP::ldapUid. Users can be
imported in courses, groups... with First name last name.