Restructure MVD code

The MVD code now follows the the code layout as all the other detectors. There is code in core/detectors/mvd which is build into the CbmMvdBase library and contains functionality which is needed by simulation, reconstruction or analysis code. The specific code for simulation, reconstruction and analysis is in the specific directories and generates specific libraries CbmMvdSim, CbmMvdReco and CbmMvdAna.

Comparing results before and after the change show either identical results or rather small changes which compared using a Kolmogorov test are classified as coming from the same distribution.