[heroes] Removed keyserver from monitoring

Hi all, since the monitoring has been complaining about the keyserver being down for months and it is unlikely that it will ever come back in its current form, I've removed the service along with all services from our monitoring. I need to double-check if the VM is still lying around, but probably it can also be wiped and the resources made available again. Any objections? Best regards, Karol Babioch