A port of cbm::algo::UnpackMuch and related classes to the XPU framework. Results of the original unpacker are reproduced on the CPU (tested on the first timeslice of the 2391_node8_0_0008.tsa file).
A port of CbmMuchDigi to XPU is needed for GPU execution. The code is hence not tested on the GPU, but previous experience suggests that the transition is unlikely to cause problems.
Includes all commits from !1107 (merged) (STS XPU unpacker) and should be merged subsequently. The same task reco/tasks/CbmTaskUnpackXpu.cxx is used for both unpackers.
