Tutorials on fluid-fluid coupling with the preCICE OpenFOAM adapter

[thesamriel]

This pull request updates and adds tutorials on fluid-fluid coupling with the OpenFOAM adapter.

Partitioned Pipe:

• Updated to use the ffep pressure boundary condition for pimpledFoam
• Explain problems of a skewed mesh with demonstration

Partitioned Flow over Backwards Facing Step:

• Showcase the inlet-outlet boundary conditions for pressure and velocity

Flow over Heated Plate with Flow Partitioning:

• modified flow-over-heated-plate tutorial with additional flow partitioning
• Showcases compatibility of the FF module with the compressible solver buoyantPimpleFoam
• Additional coupling of temperature
• FF coupling is serial-implicit, CHT coupling serial-explicit

Tutorials were tested with:

• OpenFOAM v2112
• preCICE 2.5.0
• openfoam adapter on branch develop-ff

[MakisH]

This PR is already in a very good shape. Thanks for making it so clean and easy to review!

I think the only potentially interesting part is moving the flow-over-heated-plate-partitioned-flow from a composition of explicit+implicit to a multi-implicit scheme (is possible and wanted). Everything else should be very easy & quick to adjust.

[MakisH]

Also here, regarding the linting issue (bare URL), just rebase on develop.

[MakisH]

We currently have the following situation:

• These tutorials are compatible with preCICE v2, so this PR can be merged
• However, the cases need a new OpenFOAM adapter release (or a specific branch) to work
• At the same time, we have not yet updated the cases to work with preCICE develop. This, we can do in a separate PR.

@thesamriel Please add note alerts at the top of every tutorial, explaining the dependencies. I don't think we can have a new adapter release today, so refer to preCICE v2 and your adapter branch for now.