Add date and zoom to charts in web UI

[andrewbaldwin44]

Proposal

• Stats history will now record a full UTC timestamp when recording history
• The frontend will keep a list of UTC timestamps for the charts to use
• The x-axis will format the timestamp in hours (same as before)
• The tooltip will format the timestamp as a locale string (with the date and hours, same as the HTML report)
• Add zoom functionality to the charts, which is a feature available in echarts
  

[cyberw]

Awesome stuff!

[cyberw]

Can you maybe round the response times to .01ms precision?

[andrewbaldwin44]

On the frontend we only record the chart data every 2 seconds and on the backend we record the history every 5 seconds. I'm not sure it would be useful to display milliseconds?