SDAP: Add option to disable use of Token-Groups
    
    Disabling use of Token-Groups is mandatory if expansion of nested groups is not
    desired (ldap_group_nesting_level = 0) for AD provider.
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/2294
    
    Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
    (cherry picked from commit 69994add9cd4e57d40b3b7a0b1783ef2d0aa974c)