Consider replacing some setup_* notebooks with kingfisher-colab functions

[yolile]

setup_charts, setup_usability and setup_download_data_from_registry only contain functions, so we could consider moving all these functions into a library, similar to https://github.com/open-contracting/kingfisher-colab. I thought about moving them there, but I guess that one is too kingfisher-specific.

[jpmckinney]

Might as well put them there. We don’t need multiple internal libraries for Google Colab.

[yolile]

Sounds good, I will move them there when I'm done with the MVP notebooks. Having them as a library will reduce the number of components we have and also the need to update the dependent notebooks every time we change something in a function only.

[jpmckinney]

Btw I made some small changes, so maybe pull if you are working on changes.