Add client library for SID related lookups This patch add a library for client side lookups for a SID or with a SID through the calls: - sss_nss_getsidbyname - sss_nss_getsidbyid - sss_nss_getnamebysid - sss_nss_getidbysid The library is called libsss_nss_idmap and the contributed spec file will create two new packages libsss_nss_idmap and libsss_nss_idmap-devel.