CbmTrack & CbmGlobalTrack: Add Chi2 & Ndf of the time fit to track parameters

Add Chi2 and NDF of the time fit to the track classes. This change allows one to apply separate cuts on the track quality in space and in time. It is made by the request of Ilya in this issue: https://redmine.cbm.gsi.de/issues/2981

Refs #2981