Add final exercise to the Python course, which works with the scraped data

[honzajavorek]

The exercise: Build an app to analyze data from several runs, e.g. print price trend of a certain product (sony subwoofer?) Work in progress:

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## Exercises

The final challenge of this course is about interacting with your scraper programmatically using the Apify SDK.

I file this as a separate issue from #1319, because I deem it as non-essential to finalizing the Python course for now.