pyAPES (Atmosphere-PlantEcosystem Simulator in pure Python)

Master code, working towards publishable code & model description paper in GMD

Recent changes (Samuli, March-June 2023):

1. revised package structure, renamed packages
2. typing, documenting interfaces
3. Sphinx-integration for online-documentation

ToDo's:

1. Document parameters -package
2. Multi-layer model (MLM) and 2-big-leaf model versions & Notebooks as user-guides)
3. implement soil water bucket model (from SpaFhy-style)
4. Notebooks for package-level demonstrations (user guide, case-examples for GMD)
5. debug dependencies
6. add checks on installed modules

Future developments:

1. Sapflow and trunk water storage dynamics using 1D porous media approach
2. Energy-balance based snow scheme
3. Add 13C, 18O and 3H isotopes (external modules?)