Optional time display in a local browser timezone in web UI

[ihanick]

It's supported to have log messages in "local" time format:
#1017
but web interface still shows time "Last seen" in UTC.

orchestrator/resources/public/js/orchestrator.js

Line 263 in 96533fd

addNodeModalDataAttribute("Last seen", node.LastSeenTimestamp + " (" + node.SecondsSinceLastSeen.Int64 + "s ago)");

It could be converted to the browser's time format with:

  addNodeModalDataAttribute("Last seen", (new Date(Date.parse(node.LastSeenTimestamp+"+00:00"))).toLocaleString("en-US") + " (" + node.SecondsSinceLastSeen.Int64 + "s ago)");

Same applied to: instance.DowntimeEndTimestamp / node.DowntimeEndTimestamp