It was apparently not used.

If you should ever need something like this in the future,
please use periodicbasis.hh from dune-functions.

This used to work A Long Time Ago, but the feature was removed
eventually.  Unfortunately, the code still used to build,
but failed to produce the correct result.  More recently,
some other commit in dune-functions apparently now leads to
a build failure when trying to call 'interpolate' for a
vector-valued function and a scalar basis.  This is nice!
It allows to catch errors earlier.

The old style has been deprecated for a long time, and is not
supported by dune-fufem anymore.

(In particular, the code discretizationerror.hh now requires
functions to satisfy the dune-functions function interface.)

In the wake of this, compute-disc-error.cc gets a number
of changes.  Let's hope I didn't screw up anything.

There are two important changes:  First of all, the new class implements
the `dune-functions` interface rather than the deprecated one based
on inheritance from `VirtualGridViewFunction`. Secondly, the new class
does not hard-wire geodesic interpolation anymore.  Rather, you can
give it interpolation classes which then govern how interpolation is done.

This change was long overdue.  It was now needed to make
gradient-flow.cc compile with the post 2.9 version of dune-fufem again.

In particular:
- Use the CosseratVTKWriter also for MIXED_SPACE = 1, only print out the deformation though
- Use a SubsamplingVTKWriter only for dim==gridDim==3

Use the grid function provided by the gmsh4-reader as the stressfreegridfunction in nonplanarcosseratshellenergy

The multiplication by operator* between a ScaledIdentityMatrix
and a FieldMatrix only got introduced in Dune 2.9.  Therefore,
avoid it if we are building with earlier versions of Dune.

To build these combinations with the CI-system, install foamgrid for the tests with parmg, vtk, curvedgeometry and curvedgrid

This is needed to actually compare the 3D-model with the 2D-approximation

Deprecate the call to energy with a RigidBodyMotion in cosseratenergystiffness and in nonplanarcosseratenergystiffness - this is actually duplicate code!

They can't be removed yet because they are still used in tests though!

Correct the stopping criterion in the Riemannian-TR-Solver, Riemannian-PN-Solver and MixedRiemannian-TR-Solver

Do not stop if the correction gets small because the trust region radius gets small or the regularization parameter gets large

In particular:
* add flag "useAlternativeEnergyWCoss" to NonplanarCosseratShellEnergy
* if the flag set to true, the model from the paper "Alternative derivation of the higher-order constitudtive model for six-parameter elastic shells", equations (119) and (126) is used

In particular:
* Forward declaring ProductManifold in the `impl` namespace
  is not a good idea.
* Add missing headers

targetspacetest.cc is extended to test for the first issue.

Using FieldMatrix<,1,1> for scalars has been the standard Dune way
for a long time, but since dune 2.7 using scalars directly works
just as well.

They are getting removed now for good after the release of
dune-fufem 2.9.  The code that replaces them has been there
for quite a while, and therefore we can simply use it
without having to worry about compatibility with older
dune-fufem versions.

This fixed the following error when building with GCC 12.1.0-8 (Debian):

```
/src/dune-gfe/dune/gfe/rotation.hh:225:42: error: invalid declarator before 'axis'
  225 |     Rotation<T,3>(Dune::FieldVector<T,3> axis, T angle)
      |                                          ^~~~
/src/dune-gfe/dune/gfe/rotation.hh:225:41: error: expected ')' before 'axis'
  225 |     Rotation<T,3>(Dune::FieldVector<T,3> axis, T angle)
      |                  ~                      ^~~~~
      |                                         )
```

Only include the multiplication of a ScaledIdentityMatrix with another FieldMatrix if dune common is older or equal 2.8