Restructuring/Cleanup Move MpdTpcClusterFinderTask into legacy folder (the class is obsolete and no longer used)

These classes are no longer used:

• MpdTpcClusterFinderTask
• MpdTpcClusterFinderQAHistograms
• MpdTpcPeak
• MpdTpcFoundHit

They should be removed from build and moved to folder /detectors/tpc/legacy/ .