Incorporate the carbon-nitroge code by Jingjing Liang

[hzheng88]

Xitian and @JJingL have incoporate the nitrogen dynamics into Noah-MP.

• Cai, X., Yang, Z.-L., Fisher, J. B., Zhang, X., Barlage, M., & Chen, F. (2016). Integration of nitrogen dynamics into the Noah-MP land surface model v1.1 for climate and environmental predictions. Geoscientific Model Development, 9(1), 1–15. https://doi.org/10.5194/gmd-9-1-2016
• Liang, J., Yang, Z.-L., Cai, X., Lin, P., Zheng, H., & Bian, Q. (n.d.). Modeling the impacts of nitrogen dynamics on regional terrestrial carbon and water cycles over China with Noah-MP-CN. Advances in Atmospheric Sciences. https://doi.org/10.1007/s00376-020-9231-6

The development is based on an older version of Noah-MP. This issue aims at rebasing the code to WRF 4.1.2.

• [ ] successful compilation
• [ ] namelist for the carbon-nitrogen module
• [ ] input data

[hzheng88]

The code used in https://doi.org/10.1007/s00376-020-9231-6 has be pushed as commit b15f68b.