Adding exogenous data to prettymaps

[pedrocadahia]

it would be great to add external data to do color editing in this library, main organizations need this nice plots to show findings.
So a first approach to power up this library would be to use a feature based on a geography level, let's say population by postcode, so practitioners can show their findings. I imagine this library like a complement for showing geospatial models predictions for several use cases.