Previously, it expected two factor spaces, as separate template
parameters.  Taking a single ProductManifold type is more consistent
with GeodesicFEAssembler, and it allows to eventually generalize
the code to more factors, if desired.

... but disallow a plain pointer.  This increases consistency with the
GeodesicFEAssembler class.

They do the same thing, essentially.

This is what the non-mixed ADOL-C assembler does, and I want to
merge the two.

The new method is Fufem::markBoundaryPatchDofs, which apparently
works in just the same way.

The ProductManifold class generalizes RigidBodyMotion, and can do
everything that the RigidBodyMotion class can.  Therefore there is
no point in keeping RigidBodyMotion any longer.  Having two
implementations for the same thing will just confuse people.

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

This only works for gmsh-files with version 4 or 5, but this is what we want

Add option to define deformation Dirichlet values for each direction separately in cosserat-continuum

Make GFE_ORDER and LFE_ORDER compiler macros and build the necessary combinations of cosserat-continuum-Xd-in-Xd

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

Instead of loading the volume load as a fixed (x,y,z) vector, load it as a space-dependent Python function

Correct the dimension of the rotation and the deformation in the compositeBasis, it needs to be 3, independent of dim

Correct the sign of the Neumann and volume forces to make it consistent throughout dune-gfe and dune-elasticity

In the energy file, the energies are *added*.
The Neumann and volume forces get the correct sign in the actual program file by mulitplying with (-homotopyParameter).

WHITESAPCES for previous commit: Add the option to use the Riemannian Proximal Newton solver also for problems with dim = dimwold

Use cholmod if the dune-solvers version >= 2.8, use umfpack for older versions

Now all combinations of dim = dimworld or dim != dimworld and MIXED_SPACE = 0 or MIXED_SPACE = 1 at least compile.

This has to be dimworld and not dim.

The StressFreeStateGridFunction is the actual parametrization from the grid to the
nonplanar Cosserat shell in stress-free state.
The geometries of the StressFreeStateGridFunction will then be used for all calculations
instead of the linear geometries of the piecewise linear grid.