Implement SciMLStructures interface on Parameters

[visr]

We store all parameters in a Parameters struct that we define, and sometimes run into issues regarding the assumptions of the structure of this struct. An example might be supporting autodiff, or integration with other parts of the SciML ecosystem, such as SciMLSensitivity.jl or possibly in the future Optimization.jl

SciMLStructures.jl offers an interface to describe the structure. As of 2024-02, it is still quite new and still needs to be further integrated into SciML packages, but it is good to keep an eye on it as a possible enhancement.

[visr]

In #2137 our Parameters struct was manually split into ParametersNonDiff, DiffCache and ParametersMutable for DifferentiationInterface.

@kwdef struct Parameters{C1, C2, C3, C4, C5, T}
    p_non_diff::ParametersNonDiff{C1, C2, C3, C4, C5}
    diff_cache::DiffCache{T} = DiffCache(p_non_diff)
    p_mutable::ParametersMutable = ParametersMutable()
end

SciMLStructures came up in #2137 (comment). The DifferentiationInterface feature mentioned became JuliaDiff/DifferentiationInterface.jl#749.