Change management of MPI executables in cmake post install phase

What does this MR do?

This Merge Request removes the creation of symbolic links in /usr/local/bin for MPI executables in the post install phase of cmake, so that there is no risk of overwriting an existing MPI installation on the system.

Instead, the path to the MPI executable is configured in carputils settings file, so that carputils scripts can be used with the --np option without further configuration.

One drawback with this approach is that the MPI executables are not in the PATH by default, and the user has to know where they are located if they want to use them.

Another thing is fixed in the post install phase: in some OS (CentOS for example), if the script is executed as root, then the $HOME variable contains /root. As a consequence, the carputils settings file was generated in /root in stead of the actual user's home. This was fixed and now the settings file is generated at the right place even if the script is run as root.

Author's checklist

• Follow the Contribution Guidelines.
• Describe your change in the CHANGELOG.md file in the top-level folder of the openCARP repository.
• Apply the appropriate labels.
• Does this commit add new dependencies? If yes, please evaluate carefully if the additional dependency is a more sustainable option than including the functionality in own code. If the former, describe the dependency clearly, add them to the Software Management Plan and the installation instructions (*.md files, CMake files, Docker files etc.).

Reviewer's checklist

All reviewers can help ensure accuracy, clarity, completeness, and adherence to the Contribution Guidelines.

Reviewer

• Review by a code reviewer or other selected colleague to confirm accuracy, clarity, and completeness. This can be skipped for minor fixes without substantive content changes.

Maintainer

• Review by assigned maintainer, who can always request/require the above reviews.