ToDo: Generate project files in build directory
Description
Actual behavior: If python is enabled a lot of project files are created in the source directory, see PR https://github.com/ufz/ogs/pull/272.
Expected behavior: Generated project files, like in PR https://github.com/ufz/ogs/pull/2727, should be created in the build directory. In order to enable tests using those project files in the build directory the cmake macro AddTest needs to be reworked.