[FEATURE REQUEST]Add support for exporting as SVG

[chan-max]

like this ， a new button to download svg , sometimes svg is better than png

[graphieros]

@chan-max
This feature will require to inject titles and legends in the svg during the export process, since these elements are not part of the svg.
I will keep you informed when it is done.

[graphieros]

@chan-max

The feature was added in v3.3.0