Added CMake files to doxygen exclude lists.
Added CMake files to doxygen exclude lists.

Sometimes doxygen scanned the CMake files for documentation which resulted in
wrong function graphs. Now these are excluded as pattern to avoid this bug.

RWTH-ELP/PnMPI,RWTH-HPC/PnMPI,RWTH-ELP/PnMPI,RWTH-ELP/PnMPI,RWTH-HPC/PnMPI,RWTH-HPC/PnMPI