Add computer model

[LillyG901]

Description of the issue

The ontology does not contain a way to separate the concept, implementation and the representation inside a computer of a model.
(related issues #1954, #1952)
It does however already contain numerical comptuer model. This term is similar but not broad enough for the intended use, since the existing term is limited to mathematical models.

This is a term needed for modeling uncertainties, more specifically the location of an uncertainty within a model.
See issue #1829

Ideas of solution

The term should be defined similarly to how it is described within this paper to properly work in the needed context.

Workflow checklist

• I discussed the issue with someone else than me before working on a solution
• I already read the latest version of the workflow for this repository
• The goal of this ontology is clear to me

I am aware that

• every entry in the ontology should have a definition
• classes should arise from concepts rather than from words

[stap-m]

Could you give an example for a computer model that is not a numerical computer model?
I think, for energy system modelling, the computer models used are typically numerical computer models. @areleu @Ludee @OpenEnergyPlatform/oeo-domain-expert-energy-modelling ?
We should discuss this term together with #1954 in one issue.