Cmake + ninja cleanup

Sebastian Müllerrequested to merge
muellese/mhm:cmake_ninja_cleanup into develop

Ninja had problems building mhm as dependency of mhm_pybind, since there is an issue with .. and . in paths, that then can't get resolved correctly (See link)

Also, following chs/forces!57 (merged), we shouldn't alter CMAKE_MODULE_PATH and use full paths to *.cmake files.

Edited by Sebastian Müller

Merge request reports