Add realtime/historical adapter example with wikimedia data

[melissawm]

This is a more complete example of csp features, highlighting how to write a realtime adapter and how to use the existing CSVReader adapter for historical data.

I'd be happy to hear if there are other things we want to highlight in this example, or if there are better ways to present the information. This notebook does not include the outputs since they can be very large and include visual elements. I would recommend downloading and running locally.