Pathsim chem support

[RemDelaporteMathurin]

This PR adds support for PathSim-Chem.
I'm assuming that micropip install takes care of package compatibility (between pathsim and pathsim-chem for example).

[milanofthe]

Cool! The question is if we want to import this by default or make this for example an url parameter for now. My worry is that when we have many pip installs for all the toolboxes, the initialization time before first simulation run will get longer.

Also: Does it make sense to have a different node style for the chem blocks?

[RemDelaporteMathurin]

My worry is that when we have many pip installs for all the toolboxes, the initialization time before first simulation run will get longer.

I agree! Though right now we only have one toolbox so I think it's acceptable to install it everytime and then when we have more toolboxes we can think of a way to enable plugins, a bit like how it's done in Paraview.

Also: Does it make sense to have a different node style for the chem blocks?

It might. Although to be honest at some point it may be worth considering styles for single blocks. For instance, when we add the bubble column reactor in pathsim-chem then it could be argued that it should have its own style. Same for the bubbler.

[RemDelaporteMathurin]

@milanofthe I added the GLC block from the latest pathsim-chem version. BEcause this block has non-optional arguments the input/output mapping couldn't be extracted automatically (it could've been possible if they had stayed class attributes btw ;-) ). To solve this I've added another override in extract-blocks.py