Description

Add a background map to the plots

Type of change

[x] New and adjusted code is formatted using the pre-commit hooks
[x] New and adjusted code includes type hinting now
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] The Read the Docs documentation is compiling correctly
[x] If new packages are needed, I added them the setup.py, and if needed the rtd_requirements.txt, the eDisGo_env.yml and the eDisGo_env_dev.yml.
[x] I have added new features to the corresponding whatsnew file