Remove all traces of ns-aws, ns-azure

• remove all traces of deprecated nameservers, ns-aws.sslip.io and ns-azure.sslip.io
• dig @ns-gce.sslip.io txt metrics.status.sslip.io +short returns a reasonable "Answer > 0:..." instead of weird octal characters caused by a presumptuous use of ≥; dig does not interpret UTF-8:

Old, bad:

"Answer \226\137\165 1: 67974722 (651.9/s)"

New, good:

"Answer > 0: 67974722 (651.9/s)"