[Charts] Change the charting backend from bqplot to plotly

[giswqs]

Colab already has plotly pre-installed. We can probably switch the charting backend from bqplot to plotly. The plotly FigureWidget provides similar functionality to bqplot.
https://plotly.com/python/figurewidget-app/

[jdbcode]

It seems FigureWidget is not supported by Colab. We can show a non-widget version of a plotly chart in a widgets.Output (interactive), but we can't observe interactions like a widget to, e.g., click a point in a scatter plot and have it return the feature observation info.

Here is a Colab notebook for testing: https://colab.research.google.com/drive/1X2zePfh-zO6yIWKcwOraYKrTaQe30Pzf?usp=sharing

Colab supports custom widgets, but I can't get FigureWidget to work. I'll register a bug with the Colab team.

[giswqs]

The chart module has been added in #1855. Closing this issue now.