Transition PWG4 --> PWGGA

Transition PWG4 --> PWGGA

PWG4/PartCorrBase ->  PWG/CaloTrackCorrBase
PWG4/PartCorrDep  ->  PWGGA/CaloTrackCorrelations
PWG4/GammaConv    ->  PWGGA/GammaConv

PWG4/UserTasks needs to be split (the PWGGA relevant parts
are mentioned below)

PWG4/UserTasks/CaloCellQA     ->  PWGGA/PHOSTasks/CaloCellQA
PWG4/UserTasks/PHOS_embedding ->  PWGGA/PHOSTasks/PHOS_embedding
PWG4/UserTasks/PHOS_PbPbQA    ->  PWGGA/PHOSTasks/PHOS_PbPbQA
PWG4/UserTasks/PHOS_pp_pi0    ->  PWGGA/PHOSTasks/PHOS_pp_pi0

into one library PWGGAPHOSTask.pkg

Also PWG4/omega3pi ->  PWGGA/PHOSTasks/omega3pi
should be included there as it is only one task.

PWG4/UserTasks/EmcalTasks      ->  PWGGA/EMCALTasks
into one library PWGGAEMCALTask.pkg

Split of
PWG4/CaloCalib                 ->  PWGGA/EMCALTasks

for all classes except AliAnalysisTaskCaloFilter

which goes into a new library CaloTasks which is a library
for calorimeter classes that involve EMCAL and PHOS, and
that can depend on GammaConv.

Constantin and Gustavo