Add an exchange module for the MCT

[AntoniaBerger]

Motivation
In the multi-channel exchange model, inter-channel transfer along different channels is currently handled within the unit in CADET-Core.
In the future it would be useful to have different types of exchange between different channels. These can be used, for example, for extraction or more complex counter current chromotography simulations.

Therefore it would be practical to outsource the exchange model like the binding or reaction model in CADET-Core.
This way new versions of transport can be implemented more easily and efficiently.

Work structure:

• Create a new exchange modul. #256
• Add exchange to MCT unit
• add Jacopian organization to MCT
• Implement "Langumir" exchange model
• Update Dokumentation
• Replace MCTConDispOp with normal ConDispOp
• Different exchange models in one unit ?
• Combine binding and exchange
• Add quasi-stady-state to exchange

[lieres]

We normally use the term "transport" for convection, diffusion and dispersion, .i.e. processes that impact on the spatial position of a molecule. In contrast, "binding" refers to a transition of the same molecule between different phases at the same spatial position, and "reaction" refers to the conversion of different molecules in the same phase and at the same spatial position. I would like everybody to stick to this terminology as much as possible, even though there sometimes is a grey zone. In the MCT model, the transfer of molecules from one channel to another (let's call it "inter-channel transfer") would then technically belong to the class of binding models. However, the term "binding" does not fit here. Hence, I would suggest to use an overarching term such as "phase change" to which both binding and inter-channel transfer would belong.

[AntoniaBerger]

I like "inter-channel transfer" or "transfer" for the MCT.
Another suggestion would be "inter-channel exchange" and "phase transition" as an overall term?