flow-over-plate-steady-state: Add FEniCS/FEniCS-X version

[BenjaminRodenberg]

Like described in precice/fenicsx-adapter#7 for FEniCS-X, we could add a (legacy) FEniCS version of the case here. This should be relatively easy (from the technical perspective). Finding a working compromise of codeaster-openfoam and the (planned) fenics-openfoam case might, however, be tricky. But I think this might help us to understand the existing codeaster-openfoam case better and it would be a good checkpoint on the way to integrating FEniCS-X also here. So I guess it is worth it, even if FEniCS is considered legacy.

Directly going to FEniCS-X without breaking compatibility with codeaster is from my current point of view a bit overwhelming.

The template for the FEniCS-X version is provided here: precice/fenicsx-adapter#7.

[BenjaminRodenberg]

To briefly put this issue into context: At the moment, I think the main value of adding a FEniCS version is to give another FEniCS example. Would be a nice thesis project or a project to onboard somebody. However, be aware that this would introduce a new case that we will have to maintain in the future.

I think it would be of greater value to provide a FEniCS-X version of the case. However, this also implies some development for the FEniCS-X adapter.