UTIL: move and rename sysdb_error_to_errno to utils
    
    The function sysdb_error_to_errno() is used by multiple component,
    so we want to move it to shared place. Function is renamed to
    sss_ldb_error_to_errno() and moved to util/util_errors.c.
    
    Old name is still #defined in sysdb.h and points to new
    name.
    
    Also few places where ldb error code was handled manually
    has been updated to use sss_ldb_error_to_errno.
    
    Resolves:
    https://pagure.io/SSSD/sssd/issue/3802
    
    Reviewed-by: Jakub Hrozek <jhrozek@redhat.com>
    Reviewed-by: Michal Židek <mzidek@redhat.com>