hardcoded NTP server in ObservationSummary

[markmac99]

timestampFromNTP in ObservationSummary contains a hard-coded NTP server name.

This could be an issue on managed networks such as schools, univerities and other academic institutions which do not permit unfettered outbound connections without prior agreement. In such cases, we have found we generally have to provide a complete list of IP addresses, ports, protocols and services to the org's IT security team in advance, so they can configure a suitable set of f/w rules or in some cases create a virtual subnet to isolate the RMS station as per their organizational rules.

I only noticed this because I was looking at the console while running a reprocess and an NTP timeout error popped up (and was visible because of bug #738 which prevented the usual overenthusiastic logging :) ) My own network blocks outbound NTP except from our in-house ntp server hence the attempt failed.

I suggest the NTP server should be an optional parameter in the config file so that orgs can point it at their own server if needed. Happy to work on that and create a PR for the next release. In 99% of cases it won't be required of course.

We should also document the NTP requirement in the Wiki, so that we can avoid unexpected challenges from IT security teams. I don't think there's currently anywhere on the GMN wiki that lists the IP address, port and protocol requirements for RMS so i'd be happy to add something. We have something for UKMON here so i can quickly plagiarise that!