nss-idmap: add nss like calls with timeout and flags This patch adds new calls to libsss_nss_idmap to get NSS like user and group information directly from SSSD without using the system's NSS interfaces. Additionally a timeout and a flags options are added which are not available for system's NSS. Related to https://pagure.io/SSSD/sssd/issue/2478 Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>