[Draft] Parallelization of non-bonded short-range forces with Cabana

[phohenberger]

Early Draft for the implementation of parallel computation of the non-bonded short-range kernel with the Cabana Package.

Requires a Kokkos installation from source and setting of the Kokkos_DIR environment variable to include Kokkos in the build process of ESPResSo.

Still has a lot of compatibility problems with other ESPResSo features and tests. Currently only works for non-bonded short-range forces like LJ.

[espresso-ci]

Your pull request does not meet our code formatting rules. To fix this, please do one of the following:

• You can download a patch with my suggested changes here, inspect it and make changes manually.
• You can directly apply it to your repository by running curl https://gitlab.icp.uni-stuttgart.de/espressomd/espresso/-/jobs/382095/artifacts/raw/style.patch | git apply -.
• You can run maintainer/CI/fix_style.sh to automatically fix your coding style. This is the same command that I have executed to generate the patch above, but it requires certain tools to be installed on your computer.

You can run gitlab-runner exec docker style afterwards to check if your changes worked out properly.

Please note that there are often multiple ways to correctly format code. As I am just a robot, I sometimes fail to identify the most aesthetically pleasing way. So please look over my suggested changes and adapt them where the style does not make sense.