* add GPL v3 license information to the repo and all files
* use project name `FluxProGenie`
* copyright is with MPI-BGC, and authors/contributors are listed in the AUTHORS.md
  * `##    Copyright (C) 2025 Max Planck Institute for Biogeochemistry (MPI-BGC), Jena, Germany`
  * `##    Authors and Contributors: see AUTHORS.md`
* the year of the copyright is 2025, assuming final changes for publication in this year
* does not change any actual code
* no testing is done

Closes #25