Add tests for datapackage

[OlivierCoen]

This PR is not linked to any Issue but intends to add fully anonymised data to coordo-py.

The following logic was followed to build this dataset:

Separate original Excel files into individual sheets in CSV in order to get rid of possible metadata
Change name of the person who made the survey to alice
Create completely random strings in place of all other names / messages
Replace dates by fake dates
Replace all GPS coords by random ones