add nutils solid participant

[gertjanvanzwieten]

This PR adds a solid participant compatible only with Nutils 8, formerly part of #429.

It's a draft for now because it was discovered that the system has more damping than reference results, potentially resulting from the fully implicit first order formulation. I will do some more testing in the coming days to try and sort this out.

[uekerman]

This addition goes indeed to master as it still uses preCICE v2.

[uekerman]

So the damping can be very well due to the first-order method.

[MakisH]

I have not tested this, but the changes make sense.
Merging to master is fine, but please remember backporting to develop.

[uekerman]

I could run the case, the results look reasonable and the code very clean. Thanks @gertjanvanzwieten 🙏

Let's directly merge this. We can still improve later (nonlinear model, second-order time integration).

I required to explicitly ...

pip3 install --user bottombar==2.1

Otherwise, I ran into precice/precice#1443

Patch was done here: evalf/bottombar@fd2dc3a

I will document on https://precice.org/adapter-nutils.html

[uekerman]

Linter problem seems unrelated:

MD034/no-bare-urls Bare URL used [Context: "www.openfoam.com"]

[MakisH]

Linter problem seems unrelated:

MD034/no-bare-urls Bare URL used [Context: "www.openfoam.com"]

FYI, the solution to this is disabling the MD034 linter rule in this file:

https://github.com/precice/tutorials/blob/14197c235d4a72d841b04d01446a21a227cf0639/.markdownlint.json

We already do that in develop:

https://github.com/precice/tutorials/blob/develop/.markdownlint.json

Since the master is not going to stay on for long, I guess it is not worth fixing and all the merging around.