Canopy Biomass model

[Espeer5]

Is your feature request related to a problem? Please describe. For legacy reasons, the biomass parameters of the canopy (LAI, SAI, RAI) are stored inside of the PlantHydraulics model, but are used across multiple canopy submodules.

Describe the solution you'd like The canopy should be refactored such that these biomass values live in a separate biomass submodule of the canopy. This refactoring needs to be done before spatially varying parameters can be introduced in the resolution of #596.

Additional context The simplification of the PlantHydraulics model per #599 should be completed before this refactoring is done so that the interface between the PlantHydraulics and canopy Biomass can be made clean.