MAN: Detailed ldap_group_nesting_level option
    
    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 3c1899348804713b49ba9c1f2bc782892c47c2fa)