[Feature Request] Export chart as an image

[bact]

An option for the user the download the chart as an image (PNG, etc).

Sometimes the chart is bigger than the browser window so it's not very convenient to do screenshot (as the chart will got cropped).

The image will be useful for social media sharing.

The generated image can also include:

• OONI logo (telling where this chart comes from)
• OONI URL
• Unique ID - that any user can enter this ID found on the image to OONI Explorer and can go to the same place in the dashboard (for verification that the image is not manipulated, and for any user who has interest to explore further), this will be handy as well on Instagram where a link is not clickable.
• Localized labels and legend

[Lanius-collaris]

A workaround:

Capture node screenshot with DevTools.