Create a German Map showing regional risks

[lindadelacombaz]

Closes #68. Dear @maurolepore,

Here is my PR for creating a first version of the german map. The financial data has yet to be corrected so for now, the plot is without financial data. The map is created based on the color interpolation of the high, medium and low propotion of the companies that are found in one region / postcode. For example, a region with 10% low, 10% medium and 80% high risks companies will render more of a reddish color.

For now, I have still not been able to find a way to create a meaningful scale, and I want to create an interactive map with for example the plotly library that shows the proportion of each risks categories in one region. I have talked with @AnneSchoenauer about that and I think it would be a nice implementation for the user.

Note : the main_activity column do not exists anymore in the financial data - I have hence modified some other parts of the code accordingly.

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TODO

• [x] Link related issue/PR.
• [x] Describe the goal of the PR. Avoid details that are clear in the diff.
• [x] Mark the PR as draft.
• [x] Include a unit test.
• [x] Review your own PR in "Files changed".
• [x] Ensure the PR branch is updated.
• [x] Ensure the checks pass.
• [x] Change the status from draft to ready.
• [x] Polish the PR title and description.
• [x] Assign a reviewer.

EXCEPTIONS

• [x] Slide here any item that you intentionally choose to not do.

[lindadelacombaz]

Thank you @maurolepore ! I tackled all your suggested changes, it is more structured that way, thank you :).