Introduction of the CbmGenerateMaterialMaps task

The merge request introduces a steer class CbmGenerateMaterialMaps to run the material budget map creation for different tracking stations as well as for an arbitrary set of material slices independently from the tracking routine.

At the moment the CbmGenerateMaterialMaps task is placed to the run_reco.C as an optional task. The task can be configured with a user YAML-configuration file, the example is ${VMCWORKDIR}/macro/L1/configs/material_budget_example.yaml. In the configuration file one can define a set of material slices (branch "user_slices"), the pitch ("pitch"), maximal number of bins in the material maps ("max_nof_bins"), number of rays per dimension in each bin ("nof_rays"), the ray emitting mode ("parallel_rays"). Also one can specify the "tracking_stations" flag to create the material maps for the tracking stations, provided with the tracking interfaces.