[atlas] Update on the anchoring measurements change

Dear all, As described in the labs article here: https://labs.ripe.net/Members/alun_davies/balancing-act we have split the anchoring measurements. We are currently in the process of adding more probes to the new 'probe' anchoring measurements. We expect this to be completed by the end of this week. Please let us know if you notice anything out of the ordinary. Kind regards, Johan ter Beest RIPE Atlas Team