Move here from DNS-OARC/dsc#204

Occasionally, someone manages to send a query to a NS containing '...' as the zone being queries.

This ends up as the following in the xml files:

<array name="qtype_vs_tld" dimensions="2" start_time="1562012880" stop_time="1562012940">
   <dimension number="1" type="Qtype"/>
   <dimension number="2" type="TLD"/>
   <data>
     <Qtype val="1" count="374">
       <TLD val="..." count="15"/>
       <TLD val="africa." count="10"/>
       <TLD val="co.za." count="332"/>
       <TLD val="za." count="17"/>
     </Qtype>

dsc-datatool dies when encountering this :(

Similar to my previous issue reported in April?

The dsc-datatool want to connect to 192.0.47.8 which points to `www.iana.org'.
The machine that needs to convert the data has absolutely no direct connection to the internet and will never have so.
How do I stop the datatool connecting to Icann?

• capture XML parsing errors and display an well-formed error message (with file path) instead of an stack trace

when I visit the demo site(https://dev.dns-oarc.net/dsc-grafana2/dashboard/db/dsc), i found the qps issue.
eg. try
set Time Resolution to 1m, then check the bynode qps, got avg qps: 14pps
set Time Resolution to 5m, t got avg qps: 66pps
set Time Resolution to 10m, t got avg qps: 133pps
set Time Resolution to 1h, t got avg qps: 598pps

is the avg qps right or wrong?

but from the bynode graph, the avg qps in 3hours is less then 20pps
IMHO, in different Time Resolution, the avg qps should be in the same range.

• Add quoting of measurement names, tag names and values, and values as described in https://www.docs.influxdata.com/influxdb/v1.7/write_protocols/line_protocol_reference/ (ref #31)

IANA has updated this file: https://www.iana.org/assignments/ipv6-unicast-address-assignments/ipv6-unicast-address-assignments.csv

In April, they added "Segment Routing (SRv6) SIDs" with a "status" of "ALLOCATED" but no "whois" which is causing an Exception in client_subnet_authority.py on line 68.

This file needs adjusted to handle this scenario. Anyone using the dsc-datatool with client_subnet_authority is broken at the moment due to this issue.

On the collector side, when collection is done for:
dataset second_ld_vs_rcode dns Rcode:rcode SecondLD:second_ld replies-only max-cells=50;

Sometimes queries are received for null names:

<array name="second_ld_vs_rcode" dimensions="2" start_time="1556173500" stop_time="1556173560">
  <dimension number="1" type="Rcode"/>
  <dimension number="2" type="SecondLD"/>
  <data>
    <Rcode val="0">
      <SecondLD val="org.za" count="2"/>
      <SecondLD val="" count="2"/>
      <SecondLD val="amazonaws.com" count="1"/

which ends up after DSC-datatool as

second_ld_vs_rcode,server=servername,node=ns.coza.net.za,rcode=5,secondld= value=2 1556174460000000000

which chokes when fed into 'influx -import' because of the missing value @ "secondld="

dsc-datatool needs to add a null character when encountered, to prevent the influxdb import from breaking.

Add proper logging and honor --verbose