Merge branch 'feature/snow' into 'master'

Project.toml

docs/make.jl

docs/src/api/hydrology.md

examples/heat_freeW_samoylov_snow.jl

examples/heat_vgfc_seb_samoylov_custom.jl

src/CryoGrid.jl

src/Drivers/DiffEq/DiffEq.jl

src/IO/output.jl

src/Numerics/discretize.jl

src/Numerics/grid.jl

src/Numerics/varstates.jl

src/Physics/HeatConduction/HeatConduction.jl

src/Physics/HeatConduction/heat.jl

src/Physics/Hydrology/Hydrology.jl

src/Physics/Hydrology/swrc.jl

src/Physics/Physics.jl

src/Physics/Snow/Snow.jl

src/Physics/Snow/snow_bulk.jl

src/Physics/Soils/Soils.jl

src/Physics/Soils/sfcc.jl