Major update for the TRD tracking code

Major update for the TRD tracking code
1. Detach offline tracklet from the old AliTRDseed. Prepare the junction
with AliTRDtrackletBase and remove obsolete data members
2. Store track position at lower (TPC) and upper (HMPID) entrances for
monitoring systematic effects
3. Restrict chi2 definition for tracklets to the y direction to cover up
the TPC z shift (temporary)
4. Rename and extend tracking resolution task.

Alex