add some helper function to check data synchronization
add some helper function to check data synchronization

add a check_kraken_data_synchronization
that for all instances query all engines to check that they have the
same data loaded.

used to analyse the platform, it has to be called manually (for the
moment at least)

CanalTP/fabric_navitia,CanalTP/fabric_navitia,Hoshiyo/fabric_navitia,Hoshiyo/fabric_navitia,Hoshiyo/fabric_navitia