Add Nutils participants for turek-hron-fsi3

[gertjanvanzwieten]

This PR adds two Nutils participants for the turek-hron-fsi3 tutorial. The scripts are intentionally structured similar to our monolithic example so they can be compared side by side with https://examples.nutils.org/official-turek/.

Some notes:

• The scripts are only tested in mutual coupling, so I don't know how they hold up with other participants. In particular I hope that traction is exchanged with the correct sign.
• The script requires Nutils 9, which is the currently stable version.
• The time step is set equal to the max_time_step_size, rather than the script having its own notion of a preferred time step. I'm not sure if that is idiomatic.

I hope you will find this a useful addition, let me know if anything needs changing!

[gertjanvanzwieten]

I ran both scripts through autopep8 -i but the style check is still failing. Please advise :)

[MakisH]

I ran both scripts through autopep8 -i but the style check is still failing. Please advise :)

Thanks for the PR, @gertjanvanzwieten!
Maybe this is a version issue. We are using a pre-commit hook, which you could install to get the same version. This should not mess with the rest of your system.

[gertjanvanzwieten]

For some reason actions fail to kick in but I think the scripts are compliant now, changes are generated with pre-commit run.