Add derived types for module parameter

[yoricklassmann]

Since there are a lot of parameters in the code that control many different things we should group them together into derived types.

[danielhollas]

Here's an excellent series of blog post about derived types in Fortran, we should probably take a look before starting to implement this since there are some nuances.

https://matthiasnoback.nl/tags/derived-types/

Also good ol' Dr. Fortran has some things to say: https://stevelionel.com/drfortran/2020/06/30/doctor-fortran-in-not-my-type/

[danielhollas]

@yoricklassmann feel free to take this one on as well if you're interested, I don't think I'll have time to look into it in the next two weeks (rather, I should be doing other things, so I really shoudn't look into this, even though I'd quite like to move this along :-) )

As I mentioned, a good place to start imo is the spawn parameters, which are defined in SpawnModule as individual variables atm.

[yoricklassmann]

I'll try to get to it later this week.