Deprecate caprese method categorize_dae_variables?

[dallan-keylogic]

Looking through caprese.categorize I see that there are two methods that do the same thing: categorize_dae_variables_and_constraints and categorize_dae_variables. The former seems to be more general the latter, and the latter has problems like having empty lists as default arguments (rather than using None and creating a new empty list in the function).

@Robbybp , can you tell us if categorize_dae_variables is obsolete and can be deprecated and/or removed, or whether we still need it for something?

[Robbybp]

As far as I'm aware, categorize_dae_variables is obsolete and can be deprecated. I forget the exact reason I left it in, but I think it was for a vague performance consideration - walking constraint bodies to detect differential equations could get expensive.