enable mesa_pd codegen for ci

See merge request walberla/walberla!292

heat conduction and thermal expansion showcase

See merge request !284

moved coverage image to local registry

See merge request !291

Moved from heat capacity to specific heat
to take into account individual mass of a particle.

Use serial I/O instead of MPI-IO for certain versions of OpenMPI

See merge request !282

removed mrt3 from each test case

See merge request !287

optimize build time

See merge request !290

enable clang10

See merge request !288

Renamed template parameter name.

See merge request walberla/walberla!286

See merge request walberla/walberla!285

The old name (REAL) caused problems when coupling the Trilinos library
since some component has a global define with the same name.

Codegen and cuda

Closes #116

See merge request walberla/walberla!277

use cuda as a first level language in CMake with `enable_language(CUDA)`
enable tests where cuda and codegen are both activated
various minor fixes

Please use mocks for these kind of tests.
a) deterministic
b) faster

get clangtidy10 ready

See merge request walberla/walberla!283

If you are familiar with the coupling feel free to remove the NOLINTs!

I am unsure about const correctness in the python coupling.
If you are familiar with the coupling feel free to remove the NOLINTs!

script to visualize walberla module dependencies

See merge request walberla/walberla!274