[charting] Series visibility toggling

[ttrenka]

From #1637:

Visibility toggling -- this is simply a matter of changing the "visibility" style attribute on a particular group node. The one minor issue I see is that using a grouped plotter renders all the data series under the same group node. This would preclude toggling the visibility of one particular data series. I can see the argument that perhaps this is by design since the data series are supposed to be grouped together, but on the other hand it wouldn't be any real effort to group all the data series in a grouped plotter separately.

[ttrenka]

Reassigning to Eugene and changing the milestone.