[Backlog Item]: Build a differentiable wofost72_pp

In #3, we created a prototype, where two modules leaf_dynamics and root_dynamics are differentiable wrt only TDWI and SPAN parameters.
To develop a differentiable module, we check for look-up tables, hard thresholds, and mathematical operations, and replace them with differentiable alternatives. In addition to differentiability, the implementation also focuses on efficiency, by leveraging vectorized operations.

We want to apply the same changes to all parameters of 9 modules as well as wofost72 module.

Requirements:

• tests should be there to check correctness of the model using all test data, see #27
• tests should be there to check gradients
• operations should be vectorized for both parameters and weather data (drv variable)
• documentation and docstrings should be fixed.

Examples:
See current implementations of leaf_dynamics and root_dynamics .

Note:
We use EngineTestHelper from utils to run individual model, until engine is fixed in #25

Start with the differentiable leaf_dynamics and root_dynamics implementations, then inspect the nine modules and wofost72 module linked in pcse/crop/wofost72.py. Use EngineTestHelper from utils and the test data referenced by #27 to check model correctness, then add gradient tests. Done means all parameters and drv weather operations are vectorized and the documentation and docstrings are fixed.