Add Google Colab example

[TuomasBorman]

Google Colab would enable easy testing and trying for new-comers. There could be short example notebook that is implemented with Google Colab --> now local installation needed, just Google account

https://towardsdatascience.com/how-to-use-r-in-google-colab-b6e02d736497

Even though it is designed for Python, R can be also used