Provide a be_get_account_info_send function
    
    In order to resolve group names in the simple access provider we need to
    contact the Data Provider in a generic fashion from the access provider.
    We can't call any particular implementation (like sdap_generic_send())
    because we have no idea what kind of provider is configured as the
    id_provider.
    
    This patch splits introduces the be_file_account_request() function into
    the data_provider_be module and makes it public.
    
    A future patch should make the be_get_account_info function use the
    be_get_account_info_send function.